2024 |
|
 | Anubhab Haldar, Quentin Clark, Marios Zacharias, Feliciano Giustino,; Sahar Sharifzadeh Machine learning electron-phonon interactions in two-dimensional semiconducting materials: The case of zero-point renormalization Journal Article In: Physical Review Materials, vol. 8, iss. 10, pp. L101001, 2024. @article{nokey,We utilize first-principles theory to investigate the role of electron-phonon interactions within a dataset of monolayer materials. Using density functional theory to describe excited-state transitions and the special displacement method to describe the role of phonons, we analyze the relationship between simple physical observables and electron-phonon coupling strength. For over 100 materials, we compute the band gap renormalization due to zero-point vibrational (ZPR) motion as a measure of electron-phonon interactions and train a machine learning model based on physical parameters. We demonstrate that the strength of electron-phonon interactions is highly dependent on the band gap, dielectric constant, and degree of ionicity, all of which can be physically justified. We then apply this model to 1302 2D materials, predicting the ZPR, which for five randomly selected materials tested agree well with the first-principles predictions. This work provides an approach for quantitatively predicting the ZPR as a measure of electron-phonon interactions in 2D materials. |
 | Luigi Ranalli, Carla Verdi, Marios Zacharias, Jacky Even, Feliciano Giustino,; Cesare Franchini Electron mobilities in SrTiO3 and KTaO3: Role of phonon anharmonicity, mass renormalization, and disorder Journal Article In: Physical Review Materials, vol. 8, iss. 10, pp. 104603, 2024. @article{Ranalli2024,Accurately predicting carrier mobility in strongly anharmonic solids necessitates a precise characterization of lattice dynamics as a function of temperature. We achieve consistency with experimental electron mobility data for bulk KTaO3 and SrTiO3 above 150 K by refining the Boltzmann transport equations. This refinement includes incorporating temperature-dependent anharmonic phonon eigenfrequencies and eigenmodes into the electron-phonon interaction tensor, while maintaining the derivatives of the Kohn-Sham potential as computed in density functional perturbation theory. Using efficient machine-learned force fields and the stochastic self-consistent harmonic approximation, we accurately compute the dynamical matrices. At room temperature, the calculated mobility for SrTiO3 exceeds experimental values by an order of magnitude, whereas the overestimation for KTaO3 is much less pronounced. This discrepancy is explained through the more significant electron mass renormalization near the conduction-band bottom due to anharmonic electron-phonon coupling and the presence of local disorder in SrTiO3. |
 | Viet-Anh Ha, Feliciano Giustino High-throughput screening of 2D materials identifies p-type monolayer WS2 as potential ultra-high mobility semiconductor Journal Article In: npj Computational Materials, vol. 10, iss. 1, pp. 229, 2024. @article{Ha2024,2D semiconductors offer a promising pathway to replace silicon in next-generation electronics. Among their many advantages, 2D materials possess atomically-sharp surfaces and enable scaling the channel thickness down to the monolayer limit. However, these materials exhibit comparatively lower charge carrier mobility and higher contact resistance than 3D semiconductors, making it challenging to realize high-performance devices at scale. In this work, we search for high-mobility 2D materials by combining a high-throughput screening strategy with state-of-the-art calculations based on the ab initio Boltzmann transport equation. Our analysis singles out a known transition metal dichalcogenide, monolayer WS2, as the most promising 2D semiconductor, with the potential to reach ultra-high room-temperature hole mobilities in excess of 1300 cm2/Vs should Ohmic contacts and low defect densities be achieved. Our work also highlights the importance of performing full-blown ab initio transport calculations to achieve predictive accuracy, including spin–orbital couplings, quasiparticle corrections, dipole and quadrupole long-range electron–phonon interactions, as well as scattering by point defects and extended defects. |
 | Bruno Cucco, Joshua Leveillee, Viet-Anh Ha, Jacky Even, Mikaël Kepenekian, Feliciano Giustino, George Volonakis Intrinsic Limits of Charge Carrier Mobilities in Layered Halide Perovskites Journal Article In: PRX Energy, vol. 3, iss. 2, pp. 023012, 2024. @article{Cucco2024,Layered halide perovskites have emerged as potential alternatives to three-dimensional (3D) halide perovskites due to their improved stability and larger material phase space, allowing fine tuning of structural, electronic, and optical properties. However, their charge carrier mobilities are significantly smaller than those of 3D halide perovskites, which has a considerable impact on their application in optoelectronic devices. Here, we employ state-of-the-art ab initio approaches to unveil the electron-phonon mechanisms responsible for the diminished transport properties of layered halide perovskites. Starting from a prototypical 𝐴𝑀𝑋3 halide perovskite, we model the case of 𝑛=1 and 𝑛=2 layered structures and compare their electronic and transport properties to the 3D reference. The electronic and phononic properties are investigated within density functional theory (DFT) and density functional perturbation theory (DFPT), while transport properties are obtained via the ab initio Boltzmann transport equation. The vibrational modes contributing to charge carrier scattering are investigated and associated with polar-phonon scattering mechanisms arising from the long-range Fröhlich coupling and deformation-potential scattering processes. Our investigation reveals that the lower mobilities in layered systems primarily originate from the increased electronic density of states at the vicinity of the band edges, while the electron-phonon coupling strength remains similar. Such an increase is caused by the dimensionality reduction and the break in octahedra connectivity along the stacking direction. Our findings provide a fundamental understanding of the electron-phonon coupling mechanisms in layered perovskites and highlight the intrinsic limitations of the charge carrier transport in these materials. |
 | Jon Lafuente-Bartolome, Chao Lian, Feliciano Giustino Topological polarons in halide perovskites Journal Article In: Proceedings of the National Academy of Sciences, vol. 121, iss. 21, pp. e2318151121, 2024. @article{Lafuente-Bartolome2024,Halide perovskites emerged as a revolutionary family of high-quality semiconductors for solar energy harvesting and energy-efficient lighting. There is mounting evidence that the exceptional optoelectronic properties of these materials could stem from unconventional electron–phonon couplings, and it has been suggested that the formation of polarons and self-trapped excitons could be key to understanding such properties. By performing first-principles simulations across the length scales, here we show that halide perovskites harbor a uniquely rich variety of polaronic species, including small polarons, large polarons, and charge density waves, and we explain a variety of experimental observations. We find that these emergent quasiparticles support topologically nontrivial phonon fields with quantized topological charge, making them nonmagnetic analog of the helical Bloch points found in magnetic skyrmion lattices. |
 | Sabyasachi Tiwari, Emmanouil Kioupakis, José Menendez, Feliciano Giustino Unified theory of optical absorption and luminescence including both direct and phonon-assisted processes Journal Article In: Physical Review B, vol. 109, iss. 19, pp. 195127, 2024. @article{Tiwari2024,Most semiconductors and insulators exhibit indirect band gaps, but no theory is currently available to calculate light absorption and emission spectra of these systems over a wide spectral range with predictive accuracy. The standard textbook theory of indirect absorption becomes ill-defined and yields infinite absorption strength when a photon can promote both direct and phonon-assisted transitions. As a result, state-of-the-art ab initio methods for calculating optical spectra of solids are unable to describe direct and phonon-assisted transitions on the same footing. Here, we develop a rigorous first-principles approach that overcomes this limitation by including electron-phonon correlations via many-body quasidegenerate perturbation theory. Our present formalism enables accurate calculations of the optical spectra of materials with direct, indirect, and quasidirect band gaps, and reduces to the standard theories of direct-only absorption and indirect-only absorption in the appropriate limits. We demonstrate this methodology by investigating the optical absorption spectra of silicon, germanium, gallium arsenide, and diamond. In all cases, we obtain spectra in excellent agreement with experiments. As a more ambitious test, we investigate the temperature-dependent photoluminescence of germanium, and we obtain quantitative agreement with experiments. |
 | Amanda Wang, Kyle Bushick, Nick Pant, Woncheol Lee, Xiao Zhang, Joshua Leveillee, Feliciano Giustino, Samuel Poncé, Emmanouil Kioupakis Electron mobility of SnO2 from first principles Journal Article In: Applied Physics Letters, vol. 124, iss. 17, 2024. @article{Wang2024,The transparent conducting oxide SnO2 is a wide bandgap semiconductor that is easily n-type doped and widely used in various electronic and optoelectronic applications. Experimental reports of the electron mobility of this material vary widely depending on the growth conditions and doping concentrations. In this work, we calculate the electron mobility of SnO2 from first principles to examine the temperature and doping concentration dependence and to elucidate the scattering mechanisms that limit transport. We include both electron–phonon scattering and electron-ionized impurity scattering to accurately model scattering in a doped semiconductor. We find a strongly anisotropic mobility that favors transport in the direction parallel to the c-axis. At room temperature and intrinsic carrier concentrations, the low-energy polar-optical phonon modes dominate scattering, while ionized-impurity scattering dominates above 1018 cm−3. |
 | Zhenbang Dai, Chao Lian, Jon Lafuente-Bartolome, Feliciano Giustino Excitonic polarons and self-trapped excitons from first-principles exciton-phonon couplings Journal Article In: Physical Review Letters, vol. 132, iss. 3, pp. 036902, 2024. @article{Dai2024b,Excitons consist of electrons and holes held together by their attractive Coulomb interaction. Although excitons are neutral excitations, spatial fluctuations in their charge density couple with the ions of the crystal lattice. This coupling can lower the exciton energy and lead to the formation of a localized excitonic polaron or even a self-trapped exciton in the presence of strong exciton-phonon interactions. Here, we develop a theoretical and computational approach to compute excitonic polarons and self-trapped excitons from first principles. Our methodology combines the many-body Bethe-Salpeter approach with density-functional perturbation theory and does not require explicit supercell calculations. As a proof of concept, we demonstrate our method for a compound of the halide perovskite family. |
 | Yanxing Li, Fan Zhang, Viet-Anh Ha, Yu-Chuan Lin, Chengye Dong, Qiang Gao, Zhida Liu, Xiaohui Liu, Sae Hee Ryu, Hyunsue Kim, Chris Jozwiak, Aaron Bostwick, Kenji Watanabe, Takashi Taniguchi, Bishoy Kousa, Xiaoqin Li, Eli Rotenberg, Eslam Khalaf, Joshua A. Robinson, Feliciano Giustino & Chih-Kang Shih Tuning commensurability in twisted van der Waals bilayers Journal Article In: Nature, vol. 625, pp. 494–499, 2024. @article{Li2024,Moiré superlattices based on van der Waals bilayers created at small twist angles lead to a long wavelength pattern with approximate translational symmetry. At large twist angles (θt), moiré patterns are, in general, incommensurate except for a few discrete angles. Here we show that large-angle twisted bilayers offer distinctly different platforms. More specifically, by using twisted tungsten diselenide bilayers, we create the incommensurate dodecagon quasicrystals at θt = 30° and the commensurate moiré crystals at θt = 21.8° and 38.2°. Valley-resolved scanning tunnelling spectroscopy shows disparate behaviours between moiré crystals (with translational symmetry) and quasicrystals (with broken translational symmetry). In particular, the K valley shows rich electronic structures exemplified by the formation of mini-gaps near the valence band maximum. These discoveries demonstrate that bilayers with large twist angles offer a design platform to explore moiré physics beyond those formed with small twist angles. |
 | Zhenbang Dai, Chao Lian, Jon Lafuente-Bartolome, Feliciano Giustino Theory of excitonic polarons: From models to first-principles calculations Journal Article In: Physical Review B, vol. 109, iss. 4, pp. 045202, 2024. @article{Dai2024,Excitons are neutral excitations that are composed of electrons and holes bound together by their attractive Coulomb interaction. The electron and the hole forming the exciton also interact with the underlying atomic lattice, and this interaction can lead to a trapping potential that favors exciton localization. The quasiparticle thus formed by the exciton and the surrounding lattice distortion is called excitonic polaron. Excitonic polarons have long been thought to exist in a variety of materials, and are often invoked to explain the Stokes shift between the optical absorption edge and the photoluminescence peak. However, quantitative ab initio calculations of these effects are exceedingly rare. In this manuscript, we present a theory of excitonic polarons that is amenable to first-principles calculations. We first apply this theory to model Hamiltonians for Wannier excitons experiencing Fröhlich or Holstein electron-phonon couplings. We find that, in the case of Fröhlich interactions, excitonic polarons only form when there is a significant difference between electron and hole effective masses. Then, we apply this theory to calculating excitonic polarons in lithium fluoride ab initio. The key advantage of the present approach is that it does not require supercells, therefore it can be used to study a variety of materials hosting either small or large excitonic polarons. This work constitutes the first step toward a complete ab initio many-body theory of excitonic polarons in real materials. |
2023 |
|
 | Hyungjun Lee, Samuel Poncé, Kyle Bushick, Samad Hajinazar, Jon Lafuente-Bartolome, Joshua Leveillee, Chao Lian, Francesco Macheda, Hari Paudyal, Weng Hong Sio, Marios Zacharias, Xiao Zhang, Nicola Bonini, Emmanouil Kioupakis, Elena R Margine, Feliciano Giustino Electron-phonon physics from first principles using the EPW code Journal Article In: npj Computational Materials, vol. 8, no. 156, 2023. @article{Lee2023,EPW is an open-source software for ab initio calculations of electron–phonon interactions and related materials properties. The code combines density functional perturbation theory and maximally localized Wannier functions to efficiently compute electron–phonon coupling matrix elements, and to perform predictive calculations of temperature-dependent properties and phonon-assisted quantum processes in bulk solids and low-dimensional materials. Here, we report on significant developments in the code since 2016, namely: a transport module for the calculation of charge carrier mobility under electric and magnetic fields using the Boltzmann transport equation; a superconductivity module for calculations of phonon-mediated superconductors using the anisotropic multi-band Eliashberg theory; an optics module for calculations of phonon-assisted indirect transitions; a module for the calculation of small and large polarons without supercells; and a module for calculating band structure renormalization and temperature-dependent optical spectra using the special displacement method. For each capability, we outline the methodology and implementation and provide example calculations. |
 | Marios Zacharias, George Volonakis, Feliciano Giustino, Jacky Even Anharmonic electron-phonon coupling in ultrasoft and locally disordered perovskites Journal Article In: npj Computational Materials, vol. 9, no. 153, 2023. @article{Zacharias2023b,Anharmonicity and disorder are ubiquitous in the physics of perovskites and give rise to several unique phenomena observed in scattering and spectroscopy experiments with profound consequences for device applications. Several of these phenomena still lack interpretation from a first-principles perspective since, hitherto, no approach is available to account for anharmonicity and disorder in the phonon dynamics and electron-phonon couplings. Here, relying on the special displacement method, we develop a unified framework for the treatment of both and demonstrate that electron-phonon coupling in cubic oxide and halide perovskites is strongly influenced by the multi-well potential energy landscape. We uncover that disorder is at the origin of phonon bunching and overdamping in halide perovskites leading to vibrational dynamics far from the ideal phonon picture. We also clarify a long standing problem in electronic structure calculations of cubic perovskites and show that band gap corrections arising from disorder, spin-orbit coupling, more accurate exchange-correlation functionals, and electron-phonon coupling are all essential. Our results are in excellent agreement with scattering and optical spectroscopy measurements, suggesting that disorder is the key to address pending questions on perovskites' technological applications. |
 | Marios Zacharias, George Volonakis, Feliciano Giustino, Jacky Even Anharmonic lattice dynamics via the special displacement method Journal Article In: Physical Review B, vol. 108, iss. 3, pp. 035155, 2023. @article{Zacharias2023,On the basis of the self-consistent phonon theory and the special displacement method, we develop an approach for the treatment of anharmonicity in solids. We show that this approach enables the efficient calculation of temperature-dependent anharmonic phonon dispersions, requiring very few steps to achieve minimization of the system's free energy. We demonstrate this methodology in the regime of strongly anharmonic materials, which exhibit a multiwell potential energy surface, like cubic SrTiO3, CsPbBr3, CsPbI3, CsSnI3, and Zr. Our results are in good agreement with experiments and previous first-principles studies relying on stochastic nonperturbative and molecular dynamics simulations. We achieve a very robust workflow by using harmonic phonons of the polymorphous ground state as the starting point and an iterative mixing scheme of the dynamical matrix. We also suggest that the phonons of the polymorphous ground state might provide an excellent starting approximation to explore anharmonicity. Given the simplicity, efficiency, and stability of the present treatment to anharmonicity, it is especially suitable for use with any electronic structure code and for investigating electron-phonon couplings in strongly anharmonic systems. |
 | Mir Mohammad Sadeghi, Yajie Huang, Chao Lian, Feliciano Giustino, Emanuel Tutuc, Allan H MacDonald, Takashi Taniguchi, Kenji Watanabe, Li Shi Tunable electron–flexural phonon interaction in graphene heterostructures Journal Article In: Nature, vol. 617, pp. 282-286, 2023. @article{Sadeghi2023,Peculiar electron–phonon interaction characteristics underpin the ultrahigh mobility, electron hydrodynamics superconductivity and superfluidity observed in graphene heterostructures. The Lorenz ratio between the electronic thermal conductivity and the product of the electrical conductivity and temperature provides insight into electron–phonon interactions that is inaccessible to past graphene measurements. Here we show an unusual Lorenz ratio peak in degenerate graphene near 60 kelvin and decreased peak magnitude with increased mobility. When combined with ab initio calculations of the many-body electron–phonon self-energy and analytical models, this experimental observation reveals that broken reflection symmetry in graphene heterostructures can relax a restrictive selection rule to allow quasielastic electron coupling with an odd number of flexural phonons, contributing to the increase of the Lorenz ratio towards the Sommerfeld limit at an intermediate temperature sandwiched between the low-temperature hydrodynamic regime and the inelastic electron–phonon scattering regime above 120 kelvin. In contrast to past practices of neglecting the contributions of flexural phonons to transport in two-dimensional materials, this work suggests that tunable electron–flexural phonon coupling can provide a handle to control quantum matter at the atomic scale, such as in magic-angle twisted bilayer graphene where low-energy excitations may mediate Cooper pairing of flat-band electrons. |
 | Joshua Leveillee, Xiao Zhang, Emmanouil Kioupakis, Feliciano Giustino Ab initio calculation of carrier mobility in semiconductors including ionized-impurity scattering Journal Article In: Physical Review B, vol. 107, iss. 12, pp. 125207, 2023. @article{Leveillee2023,The past decade has seen the emergence of ab initio computational methods for calculating phonon-limited carrier mobilities in semiconductors with predictive accuracy. More realistic calculations ought to take into account additional scattering mechanisms such as, for example, impurity and grain-boundary scattering. In this paper, we investigate the effect of ionized-impurity scattering on the carrier mobility. We model the analytical impurity potential parameterized from first principles by a collection of randomly distributed Coulomb scattering centers, and we include this relaxation channel into the ab initio Boltzmann transport equation, as implemented in the EPW code. We demonstrate this methodology by considering silicon, silicon carbide, and gallium phosphide, for which detailed experimental data are available. Our calculations agree well with experiments over a broad range of temperatures and impurity concentrations. For each compound investigated here, we compare the relative importance of electron-phonon scattering and ionized-impurity scattering, and we critically assess the reliability of Matthiessen's rule. We also show that an accurate description of dielectric screening and carrier effective masses can improve quantitative agreement with experiments. |
 | Weng Hong Sio, Feliciano Giustino Polarons in two-dimensional atomic crystals Journal Article In: Nature Physics, vol. 19, pp. 629-636, 2023. @article{Sio2023,Polarons are quasiparticles that emerge from the interaction of fermionic particles with bosonic fields. In crystalline solids, polarons form when electrons and holes become dressed by lattice vibrations. While experimental signatures of polarons in bulk three-dimensional materials abound–, only rarely have polarons been observed in two-dimensional atomic crystals. Here, we shed light on this asymmetry by developing a quantitative ab initio theory of polarons in atomically thin crystals. Using this conceptual framework, we determine the real-space structure of the recently observed hole polaron in hexagonal boron nitride, discover a critical condition for the existence of polarons in two-dimensional crystals and establish the key materials descriptors and the universal laws that underpin polaron physics in two dimensions. |
 | Hwijong Lee, Yuanyuan Zhou, Sungyeb Jung, Hongze Li, Zhe Cheng, Jiaming He, Jie Chen, Peter Sokalski, Andrei Dolocan, Raluca Gearba‐Dolocan, Kevin C Matthews, Feliciano Giustino, Jianshi Zhou, Li Shi High‐Pressure Synthesis and Thermal Conductivity of Semimetallic θ‐Tantalum Nitride Journal Article In: Advanced Functional Materials, vol. 33, iss. 17, no. 2370102, 2023. @article{Lee2023b,The lattice thermal conductivity (κph) of metals and semimetals is limited by phonon-phonon scattering at high temperatures and by electron-phonon scattering at low temperatures or in some systems with weak phonon-phonon scattering. Following the demonstration of a phonon band engineering approach to achieve an unusually high κph in semiconducting cubic-boron arsenide (c-BAs), recent theories have predicted ultrahigh κph of the semimetal tantalum nitride in the θ-phase (θ-TaN) with hexagonal tungsten carbide (WC) structure due to the combination of a small electron density of states near the Fermi level and a large phonon band gap, which suppress electron-phonon and three-phonon scattering, respectively. Here, measurements on the thermal and electrical transport properties of polycrystalline θ-TaN converted from the ε phase via high-pressure synthesis are reported. The measured thermal conductivity of the θ-TaN samples shows weak temperature dependence above 200 K and reaches up to 90 Wm−1K−1, one order of magnitude higher than values reported for polycrystalline ε-TaN and δ-TaN thin films. These results agree with theoretical calculations that account for phonon scattering by 100 nm-level grains and suggest κph increase above the 249 Wm−1 K−1 value predicted for single-crystal WC when the grain size of θ-TaN is increased above 400 nm. |
2022 |
|
 | Xiao Zhang, Guangsha Shi, Joshua A Leveillee, Feliciano Giustino, Emmanouil Kioupakis Ab initio theory of free-carrier absorption in semiconductors Journal Article In: Physical Review B, vol. 106, iss. 20, pp. 205203, 2022. @article{Zhang2022,The absorption of light by free carriers in semiconductors results in optical loss for all photon wavelengths. Since free-carrier absorption competes with optical transitions across the band gap, it also reduces the efficiency of optoelectronic devices such as solar cells because it does not generate electron-hole pairs. In this work, we develop a first-principles theory of free-carrier absorption taking into account both single-particle excitations and the collective Drude term, and we demonstrate its application to the case of doped Si. We determine the free-carrier absorption coefficient as a function of carrier concentration and we obtain excellent agreement with experimental data. We identify the dominant processes that contribute to free-carrier absorption at various photon wavelengths, and analyze the results to evaluate the impact of this loss mechanism on the efficiency of Si-based optoelectronic devices. |
 | Jon Lafuente-Bartolome, Chao Lian, Weng Hong Sio, Idoia G Gurtubay, Asier Eiguren, Feliciano Giustino Ab initio self-consistent many-body theory of polarons at all couplings Journal Article In: Physical Review B, vol. 106, iss. 7, pp. 075119, 2022. @article{Lafuente-Bartolome2022,We present a theoretical framework to describe polarons from first principles within a many-body Green's function formalism. Starting from a general electron-phonon Hamiltonian, we derive a self-consistent Dyson equation in which the phonon-mediated self-energy is composed by two distinct terms. One term is the Fan-Migdal self-energy and describes dynamic electron-phonon processes, the other term is a contribution to the self-energy originating from the static displacements of the atomic nuclei in the polaronic ground state. The lowest-order approximation to the present theory yields the standard many-body perturbation theory approach to electron-phonon interactions in the limit of large polarons, and the ab initio polaron equations introduced [Sio et al., Phys. Rev. B 99, 235139 (2019); Phys. Rev. Lett. 122, 246403 (2019)] in the limit of small polarons. A practical recipe to implement the present unifying formalism in first-principles calculations is outlined. We apply our method to the Fröhlich model, and obtain remarkably accurate polaron energies at all couplings, in line with Feynman's polaron theory and diagrammatic Monte Carlo calculations. We also recover the well-known results of Fröhlich and Pekar at weak and strong coupling, respectively. The present approach enables predictive many-body calculations of polarons in real materials at all couplings. |
 | Jon Lafuente-Bartolome, Chao Lian, Weng Hong Sio, Idoia G Gurtubay, Asier Eiguren, Feliciano Giustino Unified approach to polarons and phonon-induced band structure renormalization Journal Article In: Physical Review Letters, vol. 129, iss. 7, pp. 076402, 2022. @article{Lafuente-Bartolome2022b,Ab initio calculations of the phonon-induced band structure renormalization are currently based on the perturbative Allen-Heine theory and its many-body generalizations. These approaches are unsuitable to describe materials where electrons form localized polarons. Here, we develop a self-consistent, many-body Green’s function theory of band structure renormalization that incorporates localization and self-trapping. We show that the present approach reduces to the Allen-Heine theory in the weak-coupling limit, and to total energy calculations of self-trapped polarons in the strong-coupling limit. To demonstrate this methodology, we reproduce the path-integral results of Feynman and diagrammatic Monte Carlo calculations for the Fröhlich model at all couplings, and we calculate the zero point renormalization of the band gap of an ionic insulator including polaronic effects. |
Publicationssysnet2024-11-05T15:43:52+00:00
2024 |
|
| Machine learning electron-phonon interactions in two-dimensional semiconducting materials: The case of zero-point renormalization Journal Article In: Physical Review Materials, vol. 8, iss. 10, pp. L101001, 2024. |
| Electron mobilities in SrTiO3 and KTaO3: Role of phonon anharmonicity, mass renormalization, and disorder Journal Article In: Physical Review Materials, vol. 8, iss. 10, pp. 104603, 2024. |
| High-throughput screening of 2D materials identifies p-type monolayer WS2 as potential ultra-high mobility semiconductor Journal Article In: npj Computational Materials, vol. 10, iss. 1, pp. 229, 2024. |
| Intrinsic Limits of Charge Carrier Mobilities in Layered Halide Perovskites Journal Article In: PRX Energy, vol. 3, iss. 2, pp. 023012, 2024. |
| Topological polarons in halide perovskites Journal Article In: Proceedings of the National Academy of Sciences, vol. 121, iss. 21, pp. e2318151121, 2024. |
| Unified theory of optical absorption and luminescence including both direct and phonon-assisted processes Journal Article In: Physical Review B, vol. 109, iss. 19, pp. 195127, 2024. |
| Electron mobility of SnO2 from first principles Journal Article In: Applied Physics Letters, vol. 124, iss. 17, 2024. |
| Excitonic polarons and self-trapped excitons from first-principles exciton-phonon couplings Journal Article In: Physical Review Letters, vol. 132, iss. 3, pp. 036902, 2024. |
| Tuning commensurability in twisted van der Waals bilayers Journal Article In: Nature, vol. 625, pp. 494–499, 2024. |
| Theory of excitonic polarons: From models to first-principles calculations Journal Article In: Physical Review B, vol. 109, iss. 4, pp. 045202, 2024. |
2023 |
|
| Electron-phonon physics from first principles using the EPW code Journal Article In: npj Computational Materials, vol. 8, no. 156, 2023. |
| Anharmonic electron-phonon coupling in ultrasoft and locally disordered perovskites Journal Article In: npj Computational Materials, vol. 9, no. 153, 2023. |
| Anharmonic lattice dynamics via the special displacement method Journal Article In: Physical Review B, vol. 108, iss. 3, pp. 035155, 2023. |
| Tunable electron–flexural phonon interaction in graphene heterostructures Journal Article In: Nature, vol. 617, pp. 282-286, 2023. |
| Ab initio calculation of carrier mobility in semiconductors including ionized-impurity scattering Journal Article In: Physical Review B, vol. 107, iss. 12, pp. 125207, 2023. |
| Polarons in two-dimensional atomic crystals Journal Article In: Nature Physics, vol. 19, pp. 629-636, 2023. |
| High‐Pressure Synthesis and Thermal Conductivity of Semimetallic θ‐Tantalum Nitride Journal Article In: Advanced Functional Materials, vol. 33, iss. 17, no. 2370102, 2023. |
2022 |
|
| Ab initio theory of free-carrier absorption in semiconductors Journal Article In: Physical Review B, vol. 106, iss. 20, pp. 205203, 2022. |
| Ab initio self-consistent many-body theory of polarons at all couplings Journal Article In: Physical Review B, vol. 106, iss. 7, pp. 075119, 2022. |
| Unified approach to polarons and phonon-induced band structure renormalization Journal Article In: Physical Review Letters, vol. 129, iss. 7, pp. 076402, 2022. |