Enrique Macia

Complutense University of Madrid | UCM · Department of Material physics

Environmental and economic concerns have significantly spurred the search for novel, high-performance thermoelectric materials for energy conversion in small-scale power generation and refrigeration devices. This quest has been mainly fueled by the introduction of new designs and the synthesis of new materials. In fact, good thermoelectric material...

“This book beautifully traces the stellar origin of the element phosphorous, its chemical properties, and the observations of phosphorous-based molecules and minerals in the interstellar medium and in the solar system. [The author] then connects the astronomical studies with the role of phosphorous played in living organisms, presenting the biochem...

This book provides an interdisciplinary guide to quasicrystals, the 2011 Nobel Prize in Chemistry winning topic, by presenting an up-to-date and detailed introduction to the many fundamental aspects and applications of quasicrystals science. It reviews the most characteristic features of the peculiar geometric order underlying their structure and t...

The notion of biological hypercrystal may be regarded as a step toward a broader crystal notion. In this contribution I consider the geometry of cell patterns in tissues, described in terms of Voronoi tessellations and cut-and-project techniques. In this way, we realize that (1) Voronoi tessellations, early used in the description of atomic and mol...

Four decades have elapsed since the first quasiperiodic crystal was discovered in the Al-Mn alloy system, and many progresses have been made during this time interval in the science of quasicrystals (QCs). Notwithstanding this, a significant number of open questions still remain regarding both fundamental and technological aspects. For instance: Wh...

Four decades have elapsed since the first quasiperiodic crystal was discovered in the Al–Mn alloy system, and much progress has been made during this time on the science of quasicrystals (QCs). Notwithstanding this, a significant number of open questions still remain regarding both fundamental and technological aspects. For instance: What are QCs g...

Four decades have elapsed since the first quasiperiodic crystal was discovered in the Al-Mn alloy system, and many progresses have been made during this time interval in the science of quasicrystals (QCs). Notwithstanding this, a significant number of open questions still remain regarding both fundamental and technological aspects. For instance: Wh...

Four decades have elapsed since the first quasiperiodic crystal was discovered in the Al-Mn alloy system, and many progresses have been made during this time interval in the science of quasicrystals (QCs). Notwithstanding this, a significant number of open questions still remain regarding both fundamental and technological aspects. For instance: Wh...

The notion of biological hypercrystal may be regarded as a step toward a broader crystal notion. In this contribution I consider the geometry of cell patterns in tissues, described in terms of Voronoi tessellations and cut-and-project techniques. In this way, we realize that (1) Voronoi tessellations, early used in the description of atomic and mol...

Elements composing thermodynamically-stable QCs found to date belong to the broad chemical family of metals, including representatives from alkali, alkaline earth, transition metals, or rare-earth blocks. By inspecting Figure 1 we see that most main forming elements cluster in groups 11-13 and 4, whereas minority elements are mainly found among TM...

Biological systems display a broad palette of hierarchically ordered designs spanning over many orders of magnitude in size. Remarkably enough, periodic order, which profusely shows up in nonliving ordered compounds, plays a quite subsidiary role in most biological structures, which can be appropriately described in terms of the more general aperio...

Biological systems display a broad palette of hierarchically ordered designs spanning over many orders of magnitude in size. Remarkably enough, periodic order, which profusely shows up in non-living ordered compounds, plays a quite subsidiary role in most biological structures, which can be appropriately described in terms of the more general aperi...

A fully analytical treatment of the base-pair and codon dynamics in double-stranded DNA molecules is introduced, by means of a realistic treatment that considers different mass values for G, A, T, and C nucleotides and takes into account the intrinsic three-dimensional, helicoidal geometry of DNA in terms of a Hamitonian in cylindrical coordinates....

A fully analytical treatment of the base-pair and codon dynamics in double-stranded DNA 1 molecules is introduced, by means of a realistic treatment which considers different mass values 2 for G, A, T, and C nucleotides and takes into account the intrinsic three-dimensional, helicoidal 3 geometry of DNA in terms of a Hamitonian in cylindrical coord...

By introducing a suitable renormalization process, the charge carrier and phonon dynamics of a double-stranded helical DNA molecule are expressed in terms of an effective Hamiltonian describing a linear chain, where the renormalized transfer integrals explicitly depend on the relative orientations of the Watson-Crick base pairs, and the renormalize...

By introducing a suitable renormalization process the charge carrier and phonon dynamics of a double-stranded helical DNA molecule is expressed in terms of an effective Hamitonian describing a linear chain, where the renormalized transfer integrals explicitly depend on the relative orientations of the Watson-Crick base pairs, and the renormalized o...

The Special Issue on “Symmetry and Asymmetry in Quasicrystals or Amorphous Materials” aims to discuss both experimental and fundamental aspects related to the relationship between the underlying structural order and the resulting physical properties of QCs and their related approximant phases, focusing on the analogies and differences between these...

Quasicrystals (QCs) are long-range ordered materials with a symmetry incompatible with translation invariance. Accordingly, QCs exhibit high-quality diffraction patterns containing a collection of discrete Bragg reflections. Notwithstanding this, it is still common to read in the recent literature that these materials occupy an intermediate positio...

The Chemical Evolution of Phosphorus: An Interdisciplinary Approach to Astrobiology is an exploration of "the phosphorus enigma." The volume attempts to answer the questions: How did phosphorus atoms, which are produced inside the inner cores of a handful of huge stars, become concentrated in relatively high proportions in the organisms composing E...

Featured Application: Thermoelectric materials. Abstract: Quasicrystals are a class of ordered solids made of typical metallic atoms but they do not exhibit the physical properties that usually signal the presence of metallic bonding, and their electrical and thermal transport properties resemble a more semiconductor-like than metallic character. I...

https://www.preprints.org/manuscript/201905.0076/v1

Some details on this furthcoming publication: http://www.appleacademicpress.com/the-chemical-evolution-of-phosphorus-an-interdisciplinary-approach-to-astrobiology/9781771888042

A spectral classification of general one-dimensional binary aperiodic crystals (BACs) based on both their diffraction patterns and energy spectrum measures is introduced along with a systematic comparison of the zeroth-order energy spectrum main features for BACs belonging to different spectral classes, including Fibonacci-class, precious means, me...

In this work, we show that the fundamental structure of the electronic energy spectrum of binary Fibonacci quasicrystals can be decomposed in terms of two main contributions, stemming from two related characteristic symmetries. The algebraic approach, we introduce allows us for a unified and systematic description of the energy spectrum finer struc...

This Special Issue aims at gaining a deeper understanding on the relationship between the underlying structural order and the resulting physical properties in aperiodic systems, including quasicrystalline and related complex metallic alloys, photonic quasicrystals, and other structures exhibiting long-range aperiodic order. This Special Issue conta...

Photonic aperiodic structures based on the golden ratio can lead to more efficient photon management due to increased degrees of freedom in their design as compared to their periodic counterparts. In this work we will describe the thermal emission control capabilities related to the systematic use of Fibonacci multilayers and Penrose tilings in ord...

Aperiodic photonic crystals can open up novel routes for more efficient photon management due to increased degrees of freedom in their design along with the unique properties brought about by the long-range aperiodic order as compared to their periodic counterparts. In this work we first describe the fundamental notions underlying the idea of therm...

The interest in the precise nature of critical states and their role in the physics of aperiodic systems has witnessed a renewed interest in the last few years. In this work we present a review on the notion of critical wave functions and, in the light of the obtained results, we suggest the convenience of some conceptual revisions in order to prop...

In recent years, optics of aperiodic structures—artificial optical media designed on the basis of manipulation of aperiodic order—has garnered a great deal of scientific interest due to the growing number of engineering applications in nano-optics, plasmonics, and photonics technologies. Deterministic aperiodic structures, in particular, can be eff...

Since the lattice thermal conductivity of most thermoelectric materials of interest has already been greatly reduced, next generation bulk thermoelectric materials will rely on the ability to properly tailor the electronic band structure in the vicinity of the Fermi level in order to optimize their thermoelectric performance. To this end, a main th...

We study the normal modes of a duplex DNA chain at low temperatures. We consider the coupling between the hydrogen-bond radial oscillations and the twisting motion of each base pair within the Peyrard-Bishop-Dauxois model. The coupling is mediated by the stacking interaction between adjacent base pairs along the helix. We explicitly consider differ...

In this work we consider the role of aperiodic order-order without periodicity-in the design of different optical devices in one, two and three dimensions. To this end, we will first study devices based on aperiodic multilayered structures. In many instances the recourse to Fibonacci, Thue-Morse or fractal arrangements of layers results in improved...

Some time ago it was proposed on sound theoretical basis that the best thermoelectricmaterials are likely to be found among materials exhibiting a sharp singularity inthe density of states (DOS) close to the Fermi level, along with a substantial depletionof the DOS at the Fermi level. In this Chapter I will describe the thermoelectric propertiesof...

IntroductionElectronic-Structure-Related PropertiesPhononsConclusion References

The thermoelectric power of trimer oligonucleotides connected in between metallic contacts at different temperatures is theoretically studied. The obtained analytical expressions reveal the existence of important resonance effects leading to a significant thermopower enhancement for certain characteristic energies which depend on the specific elect...

Motivated by a series of experimental facts regarding anomalous transport properties in certain complex metallic alloys in this work the use of a generalized expression for the Wiedemann-Franz law is proposed in order to properly reduce experimental data concerning the phonon contribution to the thermal conductivity in a systematic way.

In this work we analyze the potential role of quasicrystals and related alloys in thermoelectric material research. Relatively large figure of merit values are expected for those samples exhibiting two properly located narrow features in the density of states close to the Fermi level. It is expected that optimized quasicrystals will perform better...

The presence of synchronized, collective twist motions of the Watson-Crick base pairs in DNA duplexes (helicoidal standing waves) can efficiently enhance the pi-pi orbital overlapping between nonconsecutive base pairs via a long-range, phonon-correlated tunneling effect. The resulting structural patterns are described within the framework of dynami...

In this work we consider the range of validity of the Wiedemann-Franz law (WFL) in quasicrystals, approximant phases, and giant unit-cell complex metallic alloys. In the limit of very low temperatures the WFL is satisfied, as expected, but as the temperature is progressively increased the Lorenz function deviates from the ideal behavior L(T)/L0=1....

Order can be found in all the structures unfolding around us at different scales, including in the arrangements of matter and in energy flow patterns. Aperiodic Structures in Condensed Matter: Fundamentals and Applications focuses on a special kind of order referred to as aperiodic order. The book covers several topics dealing with the role of ape...

Aperiodic order plays a very significant role in biology, as it determines most informative content of genomes. Amongst the various physical, chemical or biological phenomena that might be inferred from sequence correlations, charge transfer properties deserve particular attention. Indeed, the nature of DNA-mediated charge migration has been relate...

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In this work we consider the combined effect of helical structure and base-pair twist motion on charge transfer through duplex DNA at low temperatures. We present a fully analytical treatment of charge-lattice coupled dynamics in terms of nearest-neighbor tight-binding equations describing the propagation of the charge through an effective linear l...

Long range charge transfer experiments in DNA oligomers and the subsequently measured -- and very diverse -- transport response of DNA wires in solid state experiments exemplifies the need for a thorough theoretical understanding of charge migration in DNA-based natural and artificial materials. Here we present a review of tight-binding models for...

Macia in Chap. 8 discusses the thermoelectric performance of short DNA chains connected between metallic contacts at different temperatures on the basis of effective model Hamiltonians. In case of the single-stranded oligonucleotides composed of three nucleobases (codons) the presence of resonance effects leads to a significant enhancement of the t...

The European Physical Society (EPS) is a not for profit association whose members include 41 National Physical Societies in Europe, individuals from all fields of physics, and European research institutions. As a learned society, the EPS engages in activities that strengthen ties among the physicists in Europe. As a federation of National Physical...

The ξ' giant-unit-cell phase of the Al-Pd-Mn alloy system exhibits an almost temperature-independent electrical conductivity with a value typical of metallic alloys, but an anomalously low thermal conductivity comparable to that of thermal insulators. The origin of the T-independent conductivity is analysed by determining the spectral conductivity...

The validity of the Wiedemann-Franz law (WFL) for icosahedral quasicrystals belonging to the families AlCu(Fe,Ru) and AlPd(Mn,Re) is discussed. We exploit some characteristic features in the electronic structure in order to obtain closed analytical expressions for the transport coefficients in terms of the Hurwitz zeta function. Depending on the Fe...

The thermoelectric performance of PolyG-PolyC and PolyA-PolyT double-stranded chains connected between organic contacts at different temperatures is theoretically studied on the basis of an effective model Hamiltonian. The obtained analytical expressions reveal the existence of important resonance effects leading to a significant enhancement of the...

We consider a class of synthetic DNA molecules based on a quasiperiodic arrangement of their constituent nucleotides. Making use of a two-step renormalization scheme the double-stranded DNA molecule is modeled in terms of a one-dimensional effective Hamiltonian, which includes contributions from the nucleobase system, the sugar-phosphate backbone,...

In this work we introduce a similarity transformation acting on transfer matrices describing the propagation of elementary excitations through either periodic or Fibonacci lattices. The proposed transformation can act at two different scale lengths. At the atomic scale the transformation allows one to express the systems’ global transfer matrix in...

We report on a theoretical study pointing out the fundamental role of the backbone energetics in the charge transfer efficiency of polyG–polyC and polyA–polyT chains. The double-strand DNA (ds-DNA) molecules are modelled in terms of a single channel effective Hamiltonian. By introducing a two-step renormalization scheme analytical results for the e...

We study the phonon dynamics of Fibonacci heterostructures where two kinds of order (namely, periodic and quasiperiodic) coexist in the same sample at different length scales. We derive analytical expressions describing the dispersion relation of finite Fibonacci superlattices in terms of nested Chebyshev polynomials of the first and second kinds....

In this work we consider the role of aperiodic order in different domains of science and technology from an interdisciplinary approach. To start with, we introduce some general classification schemes for aperiodic arrangements of matter. Afterwards, we review the main physical properties and possible applications of quasiperiodic crystals. Several...

In this work we review the physical motivations, both experimental and theoretical, suggesting the possible use of quasicrystals as thermoelectric materials. Analytical expressions for the dimensionless thermoelectric figure of merit and the compatibility factor are discussed in order to optimize the thermoelectric performance of quasicrystals and...

The electronic structure of a quasicrystalline approximant sample is analyzed by means of a combined study of different experimental transport curves within a phenomenological approach. The main features of the obtained spectral conductivity are discussed and compared to those corresponding to icosahedral quasicrystals. Such a comparison provides i...

The thermoelectric power of short oligonucleotides connected in between metallic contacts at different temperatures is theoretically studied. The obtained analytical expressions reveal the existence of important resonance effects leading to a significant enhancement of both the electrical conductance and thermoelectric power in the case of trimer c...

In this tutorial review we consider the role of phosphorus and its compounds within the context of chemical evolution in galaxies. Following an interdisciplinary approach we first discuss the position of P among the main biogenic elements by considering its relevance in most essential biochemical functions as well as its peculiar chemistry under di...

We report on theoretical results about contact-dependent effects and tunneling currents through DNA molecules. A tetranucleotide PolyGACT chain, connected in between metallic contacts, is studied as a generic case, and compared to other periodic sequences such as PolyAT or PolyGC. Remarkable resonance conditions are analytically derived, indicating...

The thermoelectric performance of short oligonucleotides connected in between metallic contacts at different temperatures is theoretically studied on the basis of a model Hamiltonian. The obtained analytical expressions reveal the existence of important resonance effects leading to a significant enhancement of both the electrical conductance and th...

In this work we present a prospective study on the possible use of certain quasicrystalline alloys in order to improve the efficiency of segmented thermoelectric generators. To this end, we obtain a closed analytical expression for their compatibility factor [ G. J. Snyder and T. S. Ursell Phys. Rev. Lett. 91 148301 (2003)]. By comparing our analyt...

A detailed study of charge transport properties of synthetic and genomic DNA sequences is reported. Genomic sequences of the Chromosome 22, lambda-bacteriophage, and D1s80 genes of Human and Pygmy chimpanzee are considered in this work, and compared with both periodic and quasiperiodic (Fibonacci) sequences of nucleotides. Charge transfer efficienc...

In this work we present a theoretical study on the composition dependence of the thermoelectric figure of merit (ZT) of icosahedral AlPdRe quasicrystals. From our study we conclude that band-structure effects play a significant role in determining the thermoelectric performance of these alloys. By comparing our analytical results with available exp...

A detailed study of charge transport properties of synthetic and genomic DNA sequences is reported. Genomic sequences of the Chromosome 22, λ-bacteriophage, and D1s80 genes of Human and Pygmy chimpanzee are con-sidered in this work, and compared with both periodic and quasiperiodic (Fi-bonacci) sequences of nucleotides. Charge transfer efficiency i...

On the basis of a realistic model for the spectral conductivity, obtained from a proper combination of tunneling spectroscopy [R. Escudero et al., J. Phys.: Condens. Matter 11, 383 (1999)] and transport measurements, we derive a closed analytical expression for the Seebeck coefficient, satisfactorily describing its temperature dependence over a wid...

DOI:https://doi.org/10.1103/PhysRevLett.92.109901

We address the relation between long-range correlations and charge transfer efficiency in aperiodic artificial or genomic DNA sequences. Coherent charge transfer through the highest occupied molecular orbital states of the guanine nucleotide is studied using the transmission approach, and the focus is on how the sequence-dependent backscattering pr...

We investigate by analytical means the electronic transport properties of approximants and quasicrystals. The spectral resistivity is modeled by Lorentz functions in agreement with realistic ab initio calculations (linear muffin-tin orbital basis, Kubo-Greenwood formula) for low-order approximants. The analytical expressions for the transport coeff...

In this work, we introduce a phenomenological model describing the thermoelectric power of icosahedral quasicrystals. On the basis of a realistic model for the spectral conductivity, obtained from ab initio band-structure calculations [C. Landauro and H. Solbrig, Physica B 301, 267 (2000)], we derive a closed analytical expression for the Seebeck c...

In this work we report the existence of certain universal features in the temperature dependence of the electrical conductivity of Al-transition-metal icosahedral quasicrystals, extending the results previously reported on the inverse Matthiessen rule [D. Mayou, C. Berger, F. Cyrot-Lackmann, T. Klein, and P. Lanco, Phys. Rev. Lett. 70, 3915 (1993)]...

In this work we present a theoretical study on the thermal and electrical conductivities of quasicrystals. By considering a realistic model for the spectral conductivity we derive closed analytical expressions for the transport coefficients which allow us to study the temperature dependence of the Lorenz ratio L(T)=κ_e(T)/Tσ(T) at differe...

In this work, we present a theoretical study on the possible use of quasicrystals as potential thermoelectric materials. By considering a suitable model for the spectral conductivity, we show that high values of the thermoelectric figure of merit, well beyond the practical upper limit ZT=1, may be expected for certain quasicrystalline alloys. We co...

In this work we present a prospective study on the potential capabilities of optical devices based on Fibonacci dielectric multilayers. We perform a detailed analytical comparison of the linear optical response of periodic versus quasiperiodic multilayers. Based on this study we will suggest the use of hybrid-order devices, composed of both periodi...

We study the transmission of light through different kinds of Fibonacci dielectric multilayers (FDM). We exploit a transfer matrix renormalization technique previously introduced by us [E. MaciÁ, Appl. Phys. Lett. 73, 3330 (1998)] to obtain closed analytical expressions for the transmission coefficient under arbitrary incidence angle conditions. We...

A model for the electronic structure of icosahedral quasicrystals is proposed on the basis of a number of pertinent experimental results. From this model we obtain a closed analytical expression for the electrical conductivity accurately describing the most remarkable features observed in the σ(T) curves of high quality quasicrystals. As a convenie...

We consider a general Fibonacci harmonic lattice in which both the masses and the elastic constants are aperiodically arranged. Making use of a suitable decimation scheme, inspired in real-space renormalization group concepts, we obtain closed analytical expressions for the global transfer matrix and transmission coefficient for several resonant cr...

We present a theoretical analysis of quasicrystals (QCs) as potential thermoelectric materials. We consider a self-similar density of states model and extend the framework introduced in [G. D. Mahan and J. O. Sofo, Proc. Natl. Acad. Sci. U.S.A. 93, 7436 (1996)] to systems exhibiting correlated features in their electronic structure. We show that re...

We consider a general Fibonacci quasicrystal (FQC) in which both the masses and the elastic constants are aperiodically arranged. Making use of a suitable decimation scheme, inspired by real-space renormalization-group concepts, we obtain closed analytical expressions for the global transfer matrix and transmission coefficient for several resonant...

We report on the possibility of modulating the transport properties of critical normal modes in Fibonacci quasicrystals by using the mass ratio as a tuning parameter. The relationship between the spatial structure and the transport properties of these modes is studied analytically in terms of the transmission and Lyapunov coefficients. Power spectr...

81Q05 Closed and approximate solutions to the Schrödinger, Dirac, Klein-Gordon and other quantum-mechanical equations 81U20 S-matrix theory, etc.

We report the theoretical electronic structure of Fibonacci superlattices of narrow-gap III-V semiconductors. The electron dynamics is accurately described within the envelope-function approximation in a two-band model. Quasiperiodicity is introduced by considering two different III-V semiconductor layers and arranging them according to the Fibonac...

We study the resonant transmission of light through Fibonacci dielectric multilayers (FDM). Making use of a transfer matrix renormalization technique [E. Maciá and F. Domínguez-Adame, Phys. Rev. Lett. 76, 2957 (1996)] we obtain closed analytical expressions for the transmission coefficient under arbitrary incidence angle conditions. We analyze the...

In this work we extend the algebraic approach introduced in the context of general Fibonacci systems [E. Maciá and F. Domínguez-Adame, Phys. Rev. Lett. 76, 2957 (1996)] to analytically study the transmission coefficient of a subset of states in the fractal Koch lattice. We report on the existence of extended states whose transmission coefficients p...