# Jesús Carrete's research while affiliated with TU Wien and other places

## Publications (147)

Article
We use ab initio calculations to study phonon and charge-carrier transport in the Janus PtSTe monolayer, a lower-symmetry derivative of quasi-two-dimensional transition metal chalcogenides, with a view to characterizing its thermoelectric performance. For the sake of comparison, we also perform the same study on its parent structures, PtTe2 and PtS...
Article
We present BTE-Barna (Boltzmann Transport Equation - Beyond the Rta for NAnosystems), a software package that extends the Monte Carlo (MC) module of the almaBTE solver of the Peierls-Boltzmann transport equation for phonons (PBTE) to work with nanosystems based on 2D materials with complex geometries. To properly capture how the phonon occupations...
Article
HfO2 is an important high‐κ dielectric and ferroelectric, exhibiting a complex potential energy landscape with several phases close in energy. It is, however, a strongly anharmonic solid, and thus describing its temperature‐dependent behavior is methodologically challenging. An approach based on self‐consistent, effective harmonic potentials (EHP)...
Preprint
We investigate the features arising from hydrodynamic effects in graphene and phosphorene devices with finite heat sources, using ab initio calculations and solving the Phonon Boltzmann Transport Equation through energy-based deviational Monte Carlo methods. We explain the mechanisms that create those hydrodynamic features, showing that boundary sc...
Preprint
We present BTE-Barna (Boltzmann Transport Equation - Beyond the Rta for NAnosystems), a software package that extends the Monte Carlo (MC) module of the almaBTE solver of the Peierls-Boltzmann transport equation for phonons (PBTE) to work with nanosystems based on 2D materials with complex geometries. To properly capture how the phonon occupations...
Article
Full-text available
The determination of atomic structures in surface reconstructions has typically relied on structural models derived from intuition and domain knowledge. Evolutionary algorithms have emerged as powerful tools for such structure...
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Full-text available
We present NeuralIL, a model for the potential energy of an ionic liquid that accurately reproduces first-principles results with orders-of-magnitude savings in computational cost. Built on the basis of a multilayer perceptron and spherical Bessel descriptors of the atomic environments, NeuralIL is implemented in such a way as to be fully automatic...
Article
Full-text available
The promise enabled by boron arsenide’s (BAs) high thermal conductivity ( κ ) in power electronics cannot be assessed without taking into account the reduction incurred when doping the material. Using first principles calculations, we determine the κ reduction induced by different group IV impurities in BAs as a function of concentration and charge...
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Full-text available
Molecular dynamics simulations are performed to characterize the nucleation behavior of organic compounds in the gas phase. Six basic molecular species are considered—ethylene, propylene, toluene, styrene, ethylbenzene, and para-xylene—in interaction with onion-like carbon nanostructures that model soot nanoparticles (NPs) at room temperature. We i...
Preprint
HfO$_2$ is an important high-$\kappa$ dielectric and ferroelectric, exhibiting a complex potential energy landscape with several phases close in energy. It is, however, a strongly anharmonic solid, and thus describing its temperature-dependent behavior is methodologically challenging. We propose an approach based on self-consistent, effective harmo...
Article
Using first-principles calculations and Boltzmann transport theory, we study the effect of biaxial tensile strain on phonon transport in a Janus PtSTe monolayer. The band gap between the optical and acoustic phonon branches shrinks with increasing strain, resulting in a highly nonlinear monotonic decrease in the lattice thermal conductivity. That r...
Article
An energetic and dynamical stability analysis of five candidate structures—hexagonal, buckled hexagonal, litharge, inverted litharge, and distorted-NaCl—of the SnS monolayer is performed using density functional theory. The most stable is found to be a highly distorted-NaCl-type structure. The thermoelectric properties of this monolayer are then ca...
Preprint
Full-text available
We present NeuralIL, a model for the potential energy of an ionic liquid that accurately reproduces first-principles results with orders-of-magnitude savings in computational cost. Based on a multilayer perceptron and spherical Bessel descriptors of the atomic environments, NeuralIL is implemented in such a way as to be fully automatically differen...
Article
The Quantum Self-Consistent Ab-Initio Lattice Dynamics package (QSCAILD) is a python library that computes temperature-dependent effective 2nd and 3rd order interatomic force constants in crystals, including anharmonic effects. QSCAILD’s approach is based on the quantum statistics of a harmonic model. The program requires the forces acting on displ...
Article
The promise posed by half-Heusler compounds as thermoelectric materials depends on their thermal conductivity, which is strongly affected by doping. Here we elucidate the effect of p dopants on the lattice thermal conductivity (κph) of seven selected half-Heusler compounds and for twelve different substitutional defects. We unveil a strong reductio...
Article
The thermal conductivity (κ) of nonmetals is determined by the constituent atoms, the crystal structure and interatomic potentials. Although the group-IV elemental solids Si, Ge and diamond have been studied extensively, a detailed understanding of the connection between the fundamental features of their energy landscapes and their thermal transpor...
Article
Using finite-temperature phonon calculations and the Lyddane-Sachs-Teller relations, we calculate ab initio the static dielectric constants of 78 semiconducting oxides and fluorides with cubic perovskite structures at 1000 K. We first compare our method with experimental measurements, and we find that it succeeds in describing the temperature depen...
Preprint
Full-text available
The promise enabled by BAs high thermal conductivity in power electronics cannot be assessed without taking into account the reduction incurred when doping the material. Using first principles calculations, we determine the thermal conductivity reduction induced by different group IV impurities in BAs as a function of concentration and charge state...
Article
We propose a linear actuation mechanism for twisted bilayer graphene. Using molecular dynamics simulations, we show that the translational motion of a layer can cause another layer to move in an orthogonal direction. Such an effect depends strongly on the crystallographic orientation of graphene with respect to the direction of displacement. For th...
Article
Full-text available
The goal of this work is to investigate the influence of mechanical deformation on the electronic and thermoelectric properties of ZrS 3 monolayers. We employ density functional theory (DFT) calculations at the hybrid HSE06 level to evaluate the response of the electronic band gap and mobilities, as well as the thermopower, the electrical conductiv...
Preprint
We design and train a neural network (NN) model to efficiently predict the infrared spectra of interstellar polycyclic aromatic hydrocarbons (PAHs) with a computational cost many orders of magnitude lower than what a first-principles calculation would demand. The input to the NN is based on the Morgan fingerprints extracted from the skeletal formul...
Article
Full-text available
Several ternary "Janus'' metal dichalcogenides such as {Mo,Zr,Pt}-SSe have emerged as candidates with significant potential for optoelectronic, piezoelectric, and thermoelectric applications. SnSSe, a natural option to explore as a thermoelectric given that its "parent" structures are SnS2 and SnSe2 has, however, only recently been shown to be mech...
Article
Several recent studies have shown that SCAN, a functional belonging to the meta-generalized gradient approximation (MGGA) family, leads to significantly overestimated magnetic moments in itinerant ferromagnetic metals. However, this behavior is not inherent to the MGGA level of approximation since TPSS, for instance, does not lead to such severe ov...
Preprint
The Quantum Self-Consistent Ab-Initio Lattice Dynamics package (QSCAILD) is a python library that computes temperature-dependent effective 2nd and 3rd order interatomic force constants in crystals, including anharmonic effects. QSCAILD's approach is based on the quantum statistics of a harmonic model. The program requires the forces acting on displ...
Preprint
By solving the phonon and electron Boltzmann transport equations, we calculate the thermoelectric properties of three pyrite-type IIB-VIA2 dichalcogenides (ZnS2, CdS2 and CdSe2). The results show that they both have low lattice thermal conductivities and promising electrical transport properties. Comparing their detailed phonon properties with that...
Article
We report on the structural and transport properties of the smallest dislocation loop in graphene, known as a flower defect. First, by means of advanced experimental imaging techniques, we deduce how flower defects are formed during recrystallization of chemical vapor deposited graphene. We propose that the flower defects arise from a bulge type me...
Preprint
Several recent studies have shown that SCAN, a functional belonging to the meta-generalized gradient approximation (MGGA) family, leads to significantly overestimated magnetic moments in itinerant ferromagnetic metals. However, this behavior is not inherent to the MGGA level of approximation since TPSS, for instance, does not lead to such severe ov...
Article
Full-text available
We study the thermal conductivity of monolayer, bilayer, and bulk titanium trisulphide (TiS 3 ) by means of an iterative solution of the Boltzmann transport equation based on ab-initio force constants. Our results show that the thermal conductivity of these layers is anisotropic and highlight the importance of enforcing the fundamental symmetries i...
Article
Usually, the thermal conductivity is predominantly contributed by electrons in metals. In this work, by using first principles calculations we find that in WC the phonon-contributed thermal conductivities (κph) are 131 and 158 Wm−1K−1 along the a and c axes, respectively, three times as much as the electronic contribution (κe). In isotopically pure...
Preprint
Full-text available
Abstract. Many studies on the mixing state of suspended particulate matters (PM) have pointed to the role of carbon particles as nucleation seeds in the formation of atmospheric aerosols. However, the underlying physicochemical mechanisms remain unclear, particularly concerning the involvement of volatile organic compounds (VOCs) at the primary sta...
Preprint
We report on the structural and transport properties of the smallest dislocation loop in graphene, known as a flower defect. First, by means of advanced experimental imaging techniques, we deduce how flower defects are formed during recrystallization of chemical vapor deposited graphene. We propose that the flower defects arise from a bulge type me...
Article
In this work we perform molecular dynamics simulations of mixtures of a prototypical protic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), with lithium tetrafluoroborate (LiBF4), confined between two borophene walls of three different surface charges, −1, 0 and +1 e/nm², where e is the elementary charge. The properties o...
Preprint
We calculate the lattice thermal conductivities of the pyrite-type ZnSe2 at pressures of 0 and 10 GPa using the linearized phonon Boltzmann transport equation. We obtain a very low value [0.69 W/(mK) at room temperature at 0 GPa], comparable to the best thermoelectric materials. The vibrational spectrum is characterized by the isolated high-frequen...
Article
Full-text available
The mechanisms causing the reduction in lattice thermal conductivity in highly P- and B-doped Si are looked into in detail. Scattering rates of phonons by point defects, as well as by electrons, are calculated from first principles. Lattice thermal conductivities are calculated considering these scattering mechanisms both individually and together....
Preprint
The mechanisms causing the reduction in lattice thermal conductivity in highly P- and B-doped Si are looked into in detail. Scattering rates of phonons by point defects, as well as by electrons, are calculated from first principles. Lattice thermal conductivities are calculated considering these scattering mechanisms both individually and together....
Article
Using a first-principles approach, we analyze the impact of DX centers formed by S, Se, and Te dopant atoms on the thermal conductivity of GaAs. Our results are in good agreement with experiments and unveil the physics behind the drastically different effect of each kind of defect. We establish a causal chain linking the electronic structure of the...
Article
We combine state-of-the-art Green's-function methods and nonequilibrium molecular dynamics calculations to study phonon transport across the unconventional interfaces that make up crystal-phase and twinning superlattices in nanowires. We focus on two of their most paradigmatic building blocks: cubic (diamond / zincblende) and hexagonal (lonsdaleite...
Article
Achieving low thermal conductivity and good electrical properties is a crucial condition for thermal energy harvesting materials. Nanostructuring offers a very powerful tool to address both requirements: in nanostructured materials, boundaries preferentially scatter phonons compared to electrons. The computational screening for low-thermal-conducti...
Preprint
Using a first-principles approach, we analyze the impact of \textit{DX} centers formed by S, Se, and Te dopant atoms on the thermal conductivity of GaAs. Our results are in good agreement with experiments and unveil the physics behind the drastically different effect of each kind of defect. We establish a causal chain linking the electronic structu...
Article
Extrinsic spinon scattering by defects and phonons instead of intrinsic spinon-spinon coupling is responsible for resistive magnetic heat transport in one-dimensional (1D) quantum magnets. Here we report an investigation of the elusive extrinsic effect in the 1D Heisenberg S=1/2 spin chain compound Ca2CuO3, where the defect concentration is determi...
Article
Full-text available
Arsenic has been predicted to present significantly more diverse 2D phases than other elemental compounds like graphene. While practical applications must be based on finite arsenene samples, like nanoribbons, theory has so far focused on the infinite sheet. Our ab initio simulations show the clear contrast between the properties of arsenene nanori...
Article
Compositionally graded interfaces in power electronic devices eliminate dislocations but they can also decrease thermal conduction, leading to overheating. We quantify the thermal resistances of GaN/AlN graded interfaces of varying thickness using ab initio Green’s functions and compare them with the abrupt interface case. A non-trivial power depen...
Article
Full-text available
We propose a convenient method to characterize the acoustic phonon branches of 2D monolayer materials using measurements of the infrared- and Raman-active vibrational modes of nanotubes. The relations we employ are derived from a symmetry analysis based directly on the line groups of nanotubes. We perform extensive ab-initio calculations for the Mo...
Article
Full-text available
Progress in energy-related technologies demands new and improved materials with high ionic conductivities. Na- and Li-based compounds have high priority in this regard owing to their importance for batteries. This work presents a high-throughput exploration of the chemical space for such compounds. The results suggest that there are significantly f...
Article
Crystal imperfections such as dislocations strongly inuence the performance and thermal transport behavior of GaN-based devices. We show that the experimental data used to parameterize the effect of dislocations on the thermal conductivity can be explained using only the reported film thickness and point defect concentrations. The analysis highligh...
Preprint
Compositionally graded interfaces in power electronic devices eliminate dislocations, but they can also decrease thermal conduction, leading to overheating. We quantify the thermal resistances of GaN/AlN graded interfaces of varying thickness using ab initio Green's functions, and compare them with the abrupt interface case. A non-trivial power dep...
Preprint
Full-text available
Achieving low thermal conductivity and good electrical properties is a crucial condition for thermal energy harvesting materials. Nanostructuring offers a very powerful tool to address both requirements: in nanostructured materials, boundaries preferentially scatter phonons compared to electrons. The search for low-thermal-conductivity nanostructur...
Article
Full-text available
The thermal conductivities (κ) of bulk and thin-film α-Al²O³ are calculated from first principles using both the local density approximation (LDA) and the generalized gradient approximation (GGA) to exchange and correlation. The room temperature single-crystal LDA value ∼39 W/m K agrees well with the experimental values ∼35-39 W/m K, whereas the GG...
Preprint
The thermal conductivities ($\kappa$) of bulk and thin-film $\alpha$-Al$_2$O$_3$ are calculated from first principles using both the local density approximation (LDA), and the generalized gradient approximation (GGA) to exchange and correlation. The room temperature single crystal LDA value $\sim39~$W/m$~$K agrees well with the experimental values...
Preprint
Using finite-temperature phonon calculations and the Lyddane-Sachs-Teller relations, we calculate ab initio the static dielectric constant of 92 semiconducting oxides and fluorides with cubic perovskite structures at 1000 K. We first compare our method with experimental measurements, and we find that it succeeds in describing the temperature depend...
Article
Boron impurities have recently been shown to induce resonant phonon scattering in 3C-SiC, dra- matically lowering its thermal conductivity. The B-doped 3C-SiC is associated with an off-center relaxation of the B atom, inducing a local transition from Td to C3v symmetry. Similar relaxations in B and N-doped diamond, with a similarly large effect on...
Article
Single-crystal SnSe has been reported to exhibit ultralow thermal conductivity and high thermoelectric performance. For future large-scale thermoelectric applications, however, polycrystalline SnSe would offer many advantages. Unfortunately, its thermoelectric figure of merit (ZT) is much poorer than that of the single crystal. Improvements are cha...
Article
Despite vibrational properties being critical for the ab initio prediction of the finite temperature stability and transport properties of solids, their inclusion in ab initio materials repositories has been hindered by expensive computational requirements. Here we tackle the challenge, by showing that a good estimation of force constants and vibra...
Article
Determining the types and concentrations of vacancies present in intentionally doped GaN is a notoriously difficult and long-debated problem. Here we use an unconventional approach, based on thermal transport modeling, to determine the prevalence of vacancies in previous measurements. This allows us to provide conclusive evidence of the recent hypo...
Article
BoltzTraP2 is a software package for calculating a smoothed Fourier expression of periodic functions and the Onsager transport coefficients for extended systems using the linearized Boltzmann transport equation. It uses only the band and $k$-dependent quasi-particle energies, as well as the intra-band optical matrix elements and scattering rates, a...
Article
The standard theoretical understanding of the lattice thermal conductivity, $\kappa_{\ell}$, of semiconductor alloys assumes that mass disorder is the most important source of phonon scattering. In contrast, we show that the hitherto neglected contribution of force-constant (IFC) disorder is essential to accurately predict the $\kappa_{\ell}$ of th...
Article
Full-text available
The traditional paradigm for materials discovery has been recently expanded to incorporate substantial data driven research. With the intent to accelerate the development and the deployment of new technologies, the AFLOW Fleet for computational materials design automates high-throughput first principles calculations, and provides tools for data ver...
Article
Full-text available
One of the most accurate approaches for calculating lattice thermal conductivity, κ ℓ DMPSID=1, is solving the Boltzmann transport equation starting from third-order anharmonic force constants. In addition to the underlying approximations of ab-initio parameterization, two main challenges are associated with this path: high computational costs and...
Article
Full-text available
Machine learning approaches, enabled by the emergence of comprehensive databases of materials properties, are becoming a fruitful direction for materials analysis. As a result, a plethora of models have been constructed and trained on existing data to predict properties of new systems. These powerful methods allow researchers to target studies only...
Article
The cross-plane thermal conductivities of Ge-rich Si/Ge superlattices have been measured using both time-domain thermoreflectance and the differential 3 method. The superlattices were grown by molecular beam epitaxy on Ge(0 0 1) substrates. Crystal quality and structural information were investigated by x-ray diffractometry and transmission electro...
Article
Full-text available
We demonstrate an ab-initio predictive approach to computing the thermal conductivity ($\kappa$) of InAs/GaAs superlattices (SLs) of varying period, thickness, and composition. Our new experimental results illustrate how this method can yield good agreement with experiment when realistic composition profiles are used as inputs for the theoretical m...
Article
Size effects on vibrational modes in complex crystals remain largely unexplored, despite their importance in a variety of electronic and energy conversion technologies. Enabled by advances in a four-probe thermal transport measurement method, we report the observation of glass-like thermal conductivity in ~20 nm thick single crystalline ribbons of...
Article
Fe2VAl is well known as a promising candidate for thermoelectric applications due to its sharp pseudogap at the Fermi level. However, its energy conversion performance is compromised by its high thermal conductivity. Our previous studies revealed that antisite defects like AlV, AlFe and VAl are the most likely imperfections in Fe2VAl [1]. It is thu...
Article
Full-text available
Heat management in thermoelectric and power devices as well as in random access memories poses a grand challenge and can make the difference between a working and an abandoned device design. Despite the prevalence of dislocations in all these technologies, the modeling of their thermal resistance is based on 50-year-old analytical approximations, w...
Article
Machine learning (ML) is increasingly becoming a helpful tool in the search for novel functional compounds. Here we use classification via random forests to predict the stability of half-Heusler (HH) compounds, using only experimentally reported compounds as a training set. Cross-validation yields an excellent agreement between the fraction of comp...
Article
We atomistically compute the change in free energy upon binding of the globular domain of the complement protein C1q to carbon nanotubes (CNTs) and graphene in solution. Our modeling results imply that C1q is able to disaggregate and disperse bundles of large diameter multi-walled CNTs but not those of thin single-walled CNTs, and we validate this...
Article
Full-text available
Silicon carbide (SiC) is a wide band gap semiconductor with a variety of industrial applications. Among its many useful properties is its high thermal conductivity, which makes it advantageous for thermal management applications. In this paper we present \textit{ab initio} calculations of the in-plane and cross-plane thermal conductivities, $\kappa... Article Full-text available almaBTE is a software package that solves the space- and time-dependent Boltzmann transport equation for phonons, using only ab-initio calculated quantities as inputs. The program can predictively tackle phonon transport in bulk crystals and alloys, thin films, superlattices, and multiscale structures with size features in the nm-$\mu$m range. Amon... Article We use ab-initio calculations to predict the thermal conductivity of cubic SiC with different types of defects. An excellent quantitative agreement with previous experimental measurements is found. The results unveil that B$_\mathrm{C}\$ substitution has a much stronger effect than any of the other defect types in 3C-SiC, including vacancies. This f...