Questions related to Condensed Matter Physics
Quantum computers have not led to an increase in information entropy. The information theory of the second law of thermodynamics is deceptive.
Quantum computers have not led to an increase in information entropy. The information theory of the second law of thermodynamics is deceptive.
- A perpetual motion machine is a concept of engineering and outcome. It plays a small role in the first law of thermodynamics, but in the second law of thermodynamics, perpetual motion machines have become the starting point of theory, greatly improving their status. When comparing the two, it can be found that the logic of the second law of thermodynamics is filled with experiential themes, lacking rational logic, and is a loss of the rational spirit of scientists.
- In practice, scientists extensively use method B in the figure to try to find a balance between theory and experiment. This kind of thing was originally invisible, but scientists treated it as a treasure. It's quite ironic.
- Originally a trial of the second law of thermodynamics, it has become a trial of scientists. I believe there will be a response from scientists.
I am currently engaged in research involving novel heterostructures composed of various materials. In my investigation, I have observed that the Valence Band Maximum (VBM) and Conduction Band Minimum (CBM) of both parent materials are initially located at the K points. However, upon forming the heterostructures, there is a noticeable shift in the VBM and CBM to the G point. I would greatly appreciate it if anyone could recommend relevant literature or share similar findings. Thank you.
The seemingly simple question, but nobody can answer it unambiguously.
Experimental setup to the question is shown in Figure 1 in
A persistent supercurrent flows in a SC aluminum ring. Then we connect the SC aluminum ring to an aluminum wire, the second end of the wire is in a separate chamber with T > Tc (or H > Hc) and is not SC. The temperature of the SC ring is stable below Tc. Thus the SC ring is electrically connected to a non-SC zone where electron pairs dissipate their supercurrent momenta on atom lattice. Will the remote non-SC zone suppress the persistent supercurrent in the SC ring?
The answer may be very informative. Electron pairs drift between connected SC and non-SC zones. The pair density in the SC zone is not zero, in the non-SC zone — zero. Hence the pairs annihilate and arise. So paired electrons in the SC ring are not permanently paired and become single for a while. Thus, if the supercurrent decays, it is a consequence of the non-permanency of pairs. In other words, the supercurrent is eternal if its pairs are permanent (what is the case when the SC and non-SC zones are disconnected).
- η=η (T) =1-T1/T2 (excluding volume). E (V, T), P (V, T) contains volume, using η (T) Calculating E (V, T), P (V, T) does not match the experiment. This is in line with mathematical logic. The specific scientific calculations have changed their flavor. Please refer to the following figure for details
- η=η (T) =1-T1/T2 is about the ideal gas formula.
Discontinuity (artificially) of The Thermophysical Properties of NIST affects the second law of thermodynamics：
1) Scientists create Type 2 perpetual motion machines;
2) Scientists have discovered new laws of phase transition.
3) Scientists don't need to create a bunch of fake things for the second law of thermodynamics.
1）The first law of thermodynamics calculates the Carnot efficiency；
2）the second law of thermodynamics predicts: η= 1-T1/T2.
1）The first law: P=P (V, T), E=E (V, T) DE=Q-W==>η，Efficiency needs to be calculated and determined.
2）Second Law: Anti perpetual motion machine, guessing==>1-T1/T2.
1）The first law: E, P, W, Q ，η of the cyclic process can be obtained,
2）Second Law: Only efficiency can be obtained：η= 1-T1/T2.
- The uniqueness of natural science requires scientists to make choices.
- The second law of thermodynamics can only yield a single conclusion: η= 1-T1/T2（Meaningless--- lacking support from E, P, W, Q results.）Like an island in the ocean.
If someone can help me understand Helicity in the context of the High Harmonic Generation, it will be helpful. Due to mathematical notations, the exact question can be found "https://physics.stackexchange.com/questions/778274/what-is-helicity-in-high-harmonic-generation".
I want to analyze O1s peak from different samples grown at different temperature. I am confused how to compare them. I see few options like plotting them in origin and substract background. Also i can do normalization in casa xps. I tried to do by taking a reference point and also with taking average points normalization. The BG and normalization are showing different results in terms of intensity. Could you please suggest me best way to compare them? I trust BG more because that fits with min to maximum peak intensity difference when every peak is analysed separately.
Combining the pictures to see the logical flaws and deviations from the experiment of the second law of thermodynamics.
1，Please take a look at the picture: Compared to the first law of thermodynamics, the second law of thermodynamics is a pseudoscience: Perpetual motion machine is a result and engineering concept, which cannot be used as the starting point of theory (the second law)
2，In the second picture, the second law of thermodynamics was misused by scientists, indicating that this theory does not match the experiment.
3，The above two explanations indicate that the second type of perpetual motion machine exists. If you're not satisfied, you can read my other discussions or articles.
4，With the second type of perpetual motion machine, the energy and environmental crisis has been lifted. By using the electricity generated by perpetual motion machines to desalinate seawater, the Sahara desert will become fertile land, and there will be no food crisis. War and Poverty Will Move Away from Humanity
The second law of thermodynamics is difficult to solve the phase transition equilibrium of capillaries!
See pictures and links for details:
Article 1: To solve the static equilibrium of capillary liquid level.
It is almost impossible to solve the phase transition equilibrium of the capillary liquid surface. This is a test for the second law of thermodynamics.
These two papers opposing the second law of thermodynamics received "recommendations" from 10 scholars. Welcome to read.
If you think it's good, give me a "recommendation" as well.
Type 2 perpetual motion machines help humans achieve stellar civilization and eliminate it
Humans can only approach planetary level civilizations now. The following image shows the existence of type 2 perpetual motion machines, making travel and life within the solar system easier and safer.
The design of this perpetual motion machine has been recommended by two PhDs. If you support it, please provide a 'recommendation'.
What is the significance of the perpetual motion machine, the Russo Ukrainian War, and possibly the Third World War? Scientists should take on their own mission, and the key is that perpetual motion machines are indeed analyzable.
With 12 atoms, it run. But when I increased to 96 atoms, also increasing nbnd, ecutwfc, ecutrho, its showing error:
Band Structure calculation
Davidson diagonalization with overlap
c_bands: 3 eigenvalues not converged
c_bands: 2 eigenvalues not converged
c_bands: 1 eigenvalues not converged
c_bands: 3 eigenvalues not converged
c_bands: 1 eigenvalues not converged
After that the program stopped. The screenshot and the input file is given as attachment.
In general, the bandgap of compound semiconductors will decrease with the increase of the average atomic number. For example, the bandgap of CdSe is smaller than the ZnSe, and this phenomenon is very common for the II-VI group semiconductor except for the ZnO/ZnS. The bandgap of ZnO is smaller than ZnS with a smaller atomic number, which is unnatural. So does anybody know why does this happen? What mechanism dominates this uncommon phenomenon?
In the BCS theory the pair density depends on temperature, meaning that pairs can be created/annihilated by temperature variations. On the other hand, in some experiments the supercurrent, once excited, runs for many months, indicating that any pair recombination doesn’t take place (pair recombination would dissipate the initial momentum of pairs). Can we solve the contradiction?
Imagine, in a mercury ring (superconductivity below Tc=4.15 K) we establish a persistent supercurrent. Then we organize temperature cycles (T-cycles) in the cryostat, say from 3 K to 2.5 K and back. According to the BCS theory of superconductivity, the pair density decreases at warming, i.e. a not negligible fraction of pairs annihilates; the same fraction of pairs emerges back at cooling. Annihilated pairs lose their ordered supercurrent momentum on the atom lattice, so the supercurrent decreases at warming; newly created pairs do not experience any electromotive-force (EMF), since the EMF is no longer available in the ring. Hence, according to the BCS theory, the supercurrent must decrease at every T-cycle and dissipate after a number of T-cycles. However, in all experiments the supercurrent remains constant and, thus, the pair recombination (assumed in BCS) doesn’t take place (note, every cryostat device produces not negligible temperature fluctuations, so every observation of long-lived supercurrents is the experiment with T-cycles).
Do the pairs really recombine in the eternal supercurrent? Do someone know direct experiments for the temperature dependence of persistent supercurrents?
Solving this contradiction of theory/experiment we can unambiguously confirm or deny the BCS theory. So far nobody explained this paradox.
Hello all, I'm attempting to analyze the effect of defects on the electronic structure by adding them into a 4x4x4 supercell and looking at the band diagrams. I've only done band calculations for unit cells before and so wanted to clarify a couple of things. I know introducing the defects will break my symmetry (cubic) but I thought that it will still be 'near cubic' symmetry and that I could still treat it as cubic and get meaningful information by looking at those lines of symmetry (gamma to X, X to M, M to Gamma, Gamma to R, R to X and R to M). I expected to see 4x repeats along each line of symmetry due to using the supercell instead of the unit cell, but that's not what I got. Also I'm realizing that since I have an even number of super cells 0.5 0.5 0.5 is not the same point as it would be for a unit cell. Does anyone have a source for how to address this or do I just need to go through all of the geometry shifting in K Space manually? I found a couple of old links but they're all broken.
Superconducting electron pairs occur on the Fermi surface, where the electron kinetic energy is a few eV. The binding energy of paired electrons is usually a few 10-3 eV, so the electrons seemingly cannot remain paired. However, pairs are stable until thermal fluctuations destroy them. Is the situation paradoxical?
I am quite confused. I know that parallel planes do have the same Miller indices. However, as you can see from the attached XRD pattern, there is (003) family of planes having different Miller indices. Why so? What actually happening here
The thermal energy, destroying the superconducting gap, may be considered as energy of pair breaking. In other words, that is the energy, which the electron pair absorbs for breaking. The absorbable thermal energy of particle (here the electron pair) depends on the number of independent motions (degrees of freedom) of the particle. The factor 3.5 corresponds to a free particle with cylindrical symmetry, vibrating along its own cylinder axis. Does it mean the factor 3.5 of the thermal pair breaking is a thermodynamic consequence from the real-space-configuration of the electron pair?
"In crystalline solids, where the wave vector k becomes a good quantum number, the wave function can be viewed as a mapping from the k-space to a manifold in the Hilbert space (or in its projection), and hence the topology becomes relevant to electronic states in solids" - This is a statement in the introduction of Yoichi Ando's comprehensive review on topological insulators. Ref: Ando Y., Topological insulator materials, J. Phys. Soc. Japan, (2013), 82, 102001.
I find it difficult to understand why k being a good quantum number allows for the wavefunction to be viewed as a mapping from k-space to a manifold in Hilbert space. I would appreciate insights on the statement given in quotes. Other approaches to explaining why Hilbert space topology becomes relevant to electronic states in TI are also welcome. Thanks in advance.
It is well known that non-zero negative exchange energy indicates that a singlet state of electrons is energetically more favorite than a triplet one. Sufficiently strong thermal fluctuations destroy any magnetic spin order, so singlet and triplet order becomes equiprobable in the crystal. Hence below a certain temperature (say T*) the energy gain of the singlet order may be larger than the destroying thermal energy, and then preferred singlet pairs become stable. Thus the pairing energy is the difference between two energies:
E1. Energy of the stable singlet;
E2. Energy of the state without spin ordering, where singlet/triplet are equiprobable.
Note: we consider conduction electrons, i.e. electronic wave packets are much larger than lattice constant. So the result is not related with antiferromagnetic order.
This simple logic shows the electron pairing can be derived only from the non-zero negative exchange energy. Feel free to comment or to correct the result.
1. In a TI surface state/edge state, each k state exists in pairs. The Dirac cone in a 3D-TI has a -k state for every +k state.
2. Due to spin-momentum locking caused by high Spin Orbit Coupling (SOC), the -k state will possess opposite spin to that of +k.
Am I correct in understanding that the combination of these two conditions is what makes the system be termed as a time reversal symmetry protected system? That is, k needs a -k (Kramer degeneracy), and the -k state is opposite in spin also. Hence a TR operation completely reverses the state.
If yes, my question is the following:
What physical properties (band structure, crystal structure) of a system causes a material to possess the Kramer degeneracy? That is, physically what causes a material's band structure to possess k states in pairs?
But, the kramer degeneracy theorem is defined as: 'every eigen state in a TIME REVERSAL SYMMETRIC system with half integer spin will have at least one other degenerate eigen state'. This definition makes it seem like TRS is one of the requirements for the kramer degeneracy.
I am confused about which is the cause and which is the effect here? Does TRS cause the Kramer degeneracy? Or is the presence of the Kramer degeneracy along with spin-momentum locking causing the system to be called time reversal symmetry protected?
Do you consider yourself a real scientist in your field?
As for me, I don't because I don't know the answer of many basic questions in solid-state physics. For instance, from what's the energy origin of orbitalizing electrons? Is is the thermal energy at T>0 or some sort of quantum energy or both? What's exactly the group velocity of orbitalizing electronic waves and its relation to the ground state energy and thermal energy near T=0. I know there exist so many formal definitions of all the above terms! But is the exact relation between them? In particular, the quasi-free electrons in the conduction band (at T>0) what is exactly the nature of their (so-called) velocity in equilibrium, in the inter-collisional paths (between successive scattering with atoms )? Is is just their thermal velocity? or combination of this thermal velocity with some sort of quantum energy?
I would like to explain my question with the following illustrative situation. In general, when we apply pressure to the crystalline materials, the following situation arise. Pressure systematically alters the bond length, lattice parameter, volume, effective hybridization, electron density, crystal field splitting, and tunes some strong spin-orbit coupling (SOC) strength.
However, I am not able to get any direct mathematical relationship between pressure and SOC.
Is there any direct mathematical relationship between pressure and SOC of the material? If possible, could you please explain me ? If you know any relevant paper or book, could you please suggest it to me?.
Actually, I have been doing a lot of literature related to this. So far, I did not get any relevant papers that discuss the direct relationship between the pressure and SOC of the material.
Your valuable explanation, suggestion, and guidance will be very useful to our research works. Thank you very much in advance.
Most conventional theories of superconductivity (SC) use the second quantization notation (SQN) where all electrons are assumed indistinguishable, every electron can take every state in the momentum space. However, a sample shows that SQN is insensitive for supercurrent description.
For clarity we consider only 4 electrons (which may belong to arbitrary many-body system): a non-dissipative singlet pair (e1,e2) and two normal (dissipative) electrons e3, e4 . We investigate two cases, A and B:
A. The non-dissipative pair (e1,e2) is permanent. Then an initial non-zero momentum Px of the pair is also permanent. Obviously, this permanent Px is a supercurrent;
B. The non-dissipative pair (e1,e2) is not permanent, i.e. a recombination is possible: e1, e2 become normal, e3, e4 become non-dissipative and back. But at every time moment there are one non-dissipative pair and two normal electrons:
(e1,e2)singlet + e3 + e4 <=> e1 + e2 + (e3,e4)singlet
In case B the initial non-zero momentum of the pair (e1,e2) dissipates, because the electrons e1,e2 become periodically dissipative and there is no external force to give to the newly created pair (e3,e4) exactly the same momentum Px, which the pair (e1,e2) had. So the momentum Px of the system dissipates and the current vanishes. Thus non-permanent pairs cannot keep a supercurrent (otherwise the momentum conservation law is violated; the atom lattice took the momentum Px of the broken pair e1,e2, hence Px of the new pair (e3,e4) must be zero). Notable is the fact that both cases A and B are identical in SQN due to equal occupation numbers (in both cases there are exactly two normal and two SC electrons). However, the case A is superconducting and the case B is dissipative. The cause of the paradox is the indistinguishability of electrons.
Thus the SQN principle of indistinguishability of particles is insensitive to the supercurrent description, we should consider the normal and SC-electrons as distinguishable, i.e. non-exchangeable in the momentum space particles.
So far nobody could plausibly reconcile this paradox and conventional theories of SC.
I want to prepare a gap(less then 10 um) for my experment. I know silicon wafer might be a good choice(it`s easy to cleave). I try to cleave a wafer with diamond tip(or diamond pen) and push them together, but the effect was not ideal. The gap is about 20um, and the gap isn't straight enough. I want to know is there any way to get a um gap? I can also try other materials. I look forward to your suggestions.
Hello everyone, I am currently working on a Heusler alloy system which has a non-collinear magnetic order as reported by a earlier study. I intend to further explore this non-collinear magnetic state. It would be really helpful if someone can suggest me some properties that can be investigated theoretically in order to see if it has a potential use in spintronics devices or if it has some kind of other applications. I am using VASP. Thank you.
hello everyone, I am currently working on a Heusler alloy that has a very low spin polarization (below 10%). Can it still be used in spintronics devices? (usually higher spin polarization is preferred for spintronics application). Also, I should add that the antiferromagnetic state of the compound has almost twice the Magnetocrystalline Anisotropy Energy as compared to the ferromagnetic state (which is THE energetically stable state for the compound).
Hello all, I am currently working on a system that contains Pt, and when I've plotted the 2D ELF pattern, this kind of plot was obtained. So, is there any kind of explanation for these kinds of plots?
Hello. Can anyone please tell me how to set INCAR/POSCAR for AF1, AF2 magnetic structure calculation, introducing different magnetic ordering for different planes? I tried making the POSCAR file using VESTA but I am not being able to turn off the symmetry completely. I thought if I turn off the symmetry I can set MAGMOM for each individual atom of a certain plane in the INCAR file but I am not being able to do so while creating the POSCAR file using VESTA. VESTA automatically fills up each corner position of the unit cell due to symmetry and therefore when I set MAGMOM in the INCAR file, one value of MAGMOM covers all the corner points, hence not being able to set different value/direction for different corner atoms
A newest Nature paper E. T. Mannila et al, "A superconductor free of quasiparticles for seconds" https://www.nature.com/articles/s41567-021-01433-7 shows that superconducting (SC) pairs persist at least for seconds. The measurement device detects single pair-breaking-events for a large pair population, so the average life time of each pair is much longer than a few seconds (probably, many hours). Thus, every pair hosts its electrons a long time. In most SC-experiments worldwide, the measurement time is much shorter than the life time of the long-hosting SC-states, therefore we can assert that the SC-electrons and normal electrons are non-exchangeable during the measurement, i.e. the SC-electrons do not hop into normal states (at least during the resistance measurement). If so, then the SC-electrons and normal electrons are distinguishable and the superconductor has two distinguishable electronic components: (i) SC-electrons; (ii) normal electrons.
Each of the distinguishable components has its own set of quantum states, its own one-particle-wavefunction, its own Fock space, although the components are overlapped in the real space.
Mainstream theories of superconductivity (BCS etc.) operate within one electronic component and don't take into account this distinguishable 2-component-nature. Should the theories be updated according to the newest finding ?
I am new in topology in condensed matter physics. So excuse me if my question were somehow unusual. In Haldane model, we put one step (or steps) forward and take into account the annihilation and creation of the electron in the next-nearest neighbors in writing the Hamiltonian rather than the simple tight binding model, so my question is Why we do not take into account the annihilation and creation of the electron in the third, fourth and ... neighbors? Is this because those sublattices are far away ,so these hoppings are negligible?
I am currently using Wannier90 to make a site-symmetric tight-binding hamiltonian. To do this, I need all of my Wannier functions to be atomically centered. I would use site_symmetry = .true., but I cannot get the appropriate *.dmn files from VASP. In trying to get this symmetry, I attempted
num_iter = 0
to keep my functions on the atoms. In doing this, I saw how my initial WF centers were not even on my atoms, despite declaring that within my projections block in the *.win file. I found a forum post about this problem from 2016, but it was never fully resolved
Has anyone run into this problem? Or does anyone know how to fix this?
I have appended the appropriate data from my *win file, as well as the initial state from my *wout file.
4.3303193 0.0000000 0.0000001
0.0000000 4.0765639 0.0000000
0.0000006 0.0000000 29.9986600
Sn 2.5301712 2.0382820 16.9495545
Sn 0.3650114 0.0000000 13.9993643
S 0.0000909 0.0000000 16.5839284
S 2.1652504 2.0382820 14.3649879
WF centre and spread 1 ( 2.547126, 2.038268, 16.967523 ) 2.50939867
WF centre and spread 2 ( 2.574011, 2.038383, 17.581330 ) 6.41210763
WF centre and spread 3 ( 2.504668, 2.038283, 17.005189 ) 9.76083682
WF centre and spread 4 ( 2.585412, 1.992948, 16.941401 ) 28.67792149
WF centre and spread 5 ( 0.381966, -0.000014, 13.981389 ) 2.50921043
WF centre and spread 6 ( 0.408842, 0.000101, 13.367488 ) 6.41138460
WF centre and spread 7 ( 0.339537, 0.000001, 13.943767 ) 9.76017540
WF centre and spread 8 ( 0.420172, -0.045365, 14.007884 ) 28.67839428
WF centre and spread 9 ( -0.009523, 0.000005, 16.550864 ) 3.54856232
WF centre and spread 10 ( 0.003042, 0.000030, 16.521522 ) 3.07910933
WF centre and spread 11 ( -0.015094, 0.000000, 16.516322 ) 4.46905309
WF centre and spread 12 ( 0.042570, -0.005514, 16.515811 ) 10.13798770
WF centre and spread 13 ( 2.155636, 2.038287, 14.398071 ) 3.54846432
WF centre and spread 14 ( 2.168198, 2.038312, 14.427348 ) 3.07904394
WF centre and spread 15 ( 2.150072, 2.038282, 14.432612 ) 4.46881459
WF centre and spread 16 ( 2.207729, 2.032774, 14.433204 ) 10.13745989
I am doing a PhD in AdS/CMT. In order to have a better understating of the physics of the systems the correspondence aims to describe, I am looking for accessible reviews or online seminars about the mostly commonly used experimental techniques for probing strongly coupled materials such as the cuprates in their strange metal phase.
when a 2DEG is subjected to the magnetic field, the energy is split in the form of Landau levels. and the QHE is explained on that basis. however, in the case of quantized resistance is obtained without a magnetic field. then how Landau levels are formed in QSHE?
In non-local measurements, we apply current between two leads and measure voltage on different leads away from the current leads. to calculate resistance, do we need to divide the non-local voltage by current - as such current is not flowing through the voltage leads?
can you please suggest good literature on non-local measurements?
I have several confusions about the Hall and quantum Hall effect:
1. does Hall/QHE depend on the length and width of the sample?
2. Why integer quantum Hall effect is called one electron phenomenon? there are many electrons occupying in single landau level then why a single electron?
3. Can SDH oscillation be seen in 3D materials?
4. suppose if there is one edge channel and the corresponding resistance is h/e^2 then why different values such as h/3e^2, h/4e^2, h/5e^2 are measured across contacts? how contact leads change the exact quantization value and how it can be calculated depending on a number of leads?
5. how can we differentiate that observed edge conductance does not have any bulk contribution?
When a material is in a Topological state, the conduction in 2D TI is due to the edge channel. If I am using a Hall bar structure where I am doing Non-local measurements as can be seen from the attached file. Many papers say that there is edge conductance of h/e^2 corresponding to one edge channel. If in a Hall bar there are 6 terminals. this is distributed as 1:5 and each channel show h/6e^2 resistance. I do not understand why there is only h/6e^2 resistance even though voltage measurement is done at one terminal? please help
What are the quantum materials? Quantum phenomenon takes place in every material at atomic level. then how to define quantum materials? is Iron (magnetic materials) quantum material as it shows magnetism which is the quantum phenomenon? if not then what are quantum materials?
Generally, we always try to give low input to operate a device. What are the minimum values of voltage for CMOS technology and magnetic field for spintronics technology?
This RG discussion (thread) is an open teaching & learning talk about the use of the TB method in the solid-state.
TB has proven to be a very powerful no-relativistic quantum mechanical (NRQM) technic in order to match experimental data and theories in several branches of solid-state where quasiparticle excitations play the fundamental role, i. e., electrons and holes in metals, magnons and phonons, and Cooper pairs among other systems, it helps even in the physics of insulated systems where there is a gap between the conduction and the valence bands.
TB helps to understand more deeply into solids with respect to the free & nearly free electron models. The 3 methods create a wonderful picture of quasiparticles and interactions that take place in solids. In addition, with visualizing tools, TB becomes a very powerful method that can lead to important conclusions and give physical insight into STP complicated problems.
I learned the subject using the IV chapter (electron in a perfect lattice) of the classical book by Prof. Rudolph Peierls “Quantum Theory of Solids” – 1955 . Later on, the subject of TB was popularized by another couple of classical books: Prof. Ziman’s book “Principles of the Theory of Solids” – 1972  & Profs. Ashcroft and Mermin´s book “Solid State Physics”  - 1976. Finally, the TB method was magistrally exposed by Prof. W. A. Harrison, "Electronic Structure and Properties of Solids"  - 1980.
TB implies that electrons & holes which are eigenstates of the Hamiltonian are spread entirely on the crystal (like in the free & nearly free eh-models), but that they also are localized at lattice sites (free & nearly free e-models do have no such a requirement). This is a really important statement. In addition, the TB approach for example helps to understand the metal insulation transition by means of the Peierls instability & transition between metallic and insulating solid states .
Nowadays, there are important advances, both theoretical such as the one where using a TB approach Prof. Chris Nelson  still has the only model that predicted the frustration-based behavior of the structural glass transition in As2Se3, He used TB to fit experimental nuclear quadrupole resonance data (NQR). In addition, with TB there are ab initio ones using this powerful, rigorous but also, intuitive tool in the physics of the solid-state, please see for the latest news on Green functions and TB .
All RG community members are welcome to discuss and share teaching and research findings using the TB method. Thank you all in advance for your participation.
 Rudolph Peierls: Quantum theory of Solids. Clarendon Press, Oxford, 1955.
 J.M. Ziman: Principles of the Theory of Solids, Cambridge University Press, London, 1972.
 N.W. Ashcroft and N.D. Mermin: Solid State Physics, HRW International Editions, 1976.
 W. A. Harrison, Electronic Structure and Properties of Solids, Dover, New York, 1980.
 Rudolph Peierls: More Surprises in Theoretical Physics. Vol. 105. Princeton University Press, 1991.
 W. A. Harrison
 Chris Nelson, A frustration based model of the structural glass transition in As2Se3 201 Journal of Non-Crystalline Solids s 398–399:48–56
 S. Repetsky, I. Vyshyvana, S. Kruchinin, and S. Bellucci. 2020. Tight-binding model in the theory of disordered crystals. Modern Physics Letters B Vol. 34, No. 19
Dear and Distinguished Fellows from the solid-state physics RG community.
Does have anyone read after 20 years the preprint from Prof. Laughlin A Critique of two metals?
I read it when I was a PhD student. I think his opinion after 20 years deserves more attention. Please, feel free to follow down the link to the arXiv preprint if somebody has an interest and please leave your opinion:
Article A Critique of Two Metals
Just curious to make a list of recommended books/study materials explaining Magnetism in condensed matter physics preferably with emphasis on Quantum Magnetism.
I would be glad if you give some references from Bachelors to Ph.D. level.
Thanks & Regards,
In the (electro-) conducting materials, as I know, there is an energy gap between the valence band (VB) and the conduction band (CB) that can be brought to or near-to the Fermi level by doping (p-type or n-type dopant).
But ( My question is ), If I want to design a (semi- or super-) conductor's materials (inorganic or polymeric) , Which properties would I look for? and, also, Which characterizations would I consider for the properties' investigations? What are the requirements for the materials' property (with regard to its band structure) to achieve the considered structure-property relationships (or requirements ) for the preparation of the conducting materials?
I am applying top gate voltage using Al2O3 (100nm) dielectric. I would like to calculate effective elecrtic field applied using this top gate. I can apply top gate voltage of 1V (say). how much effective electric field can be obtained by 1V top gate.
Please help me
What is the Exciton's Bohrs Radius? of :
- Boron Nitride (BN)
Anyone know ?,
Or have seen one of these in a paper ?
I'll appreciate it !
The term Condensed Matter is a synonym of Solid-state Physics. Recently, many scientists and researchers replaced their field of specialty and use the term Condensed matter, with its two branches (Soft and hard Condensed matter Physics) to identify weakly-coupled and strongly coupled materials. However, condensed mater includes solids and liquids. If you are interested in these topics, which term you prefer (e.g., to talk about superconductors) and why?
What could be the reason for a charge up in a device. I noticed that when I measure the temperature dependence of resistance, at the lowest temperature there is i very sharp increase in resistance. this increase depends upon waiting time at the lowest temperature. Why device charge up with time. if I restart measurements again, it starts from the initial value.
please someone experienced this?
Generally, when we calculate the carrier density in 2DEG from SdH oscillations (Field dependence of sheet resistance) and QHE (field dependence of Hall resistance) it should match. In some cases it was found that carrier density calculated using both data differ. What is the reason behind this difference? What is the physics behind the calculation of carrier density from SdH oscillations and Hall resistance data?
Dear RG community, the unitary limit in the amplitude of dispersion * in QM is very complicated and elusive to explain, although there are firmly pieces of evidence, that unconventional superconductors such as HTCSs and Heavy Fermions are mostly in the strong scattering unitary limit at very low energies (temperatures) and a certain range of dopping by non-magnetic impurities. There are also pieces of evidence that point to the same conclusion in Fermi & Bose atomic gases ~,#.
We will publish a preprint on this topic.
I will showcase 3 references in this thread, for now:
* 1. Quantum Mechanics (non-relativistic theory) Landau & Lifshitz, Chapter XVII on elastic collisions, Pergamon, 1977.
+ 2. Superfluid Fermi liquid in a unitary regime by L. P. Pitaevskii, arXiv & Physics - Uspekhi v. 51 p. 603 (2008).
# 3. Momentum-resolved spectroscopy of a Fermi liquid E. Doggen & J. Kinnunen Scientific Reports volume 5, Article number: 9539 (2015)
I ran VASP relax calculations for Fe in the interstitial position of MgO for different charge states of Fe from 0 to +3. The magnetic moment seems to increase from 2BM to 5BM in steps of 1 as each electron is removed but it not quite consistent with the number of unpaired electrons. Is it possible that a system with a lesser number of unpaired electrons can have a higher magnetic moment?