Article
Chemistry, Multidisciplinary
Tianchun Wang, Takuya Nomoto, Takashi Koretsune, Ryotaro Arita
Summary: We performed first-principles Eliashberg calculations for several conventional superconductors, investigating the importance of self-consistency in the calculation. By comparing the self-consistent results with the one-shot calculation results for the self-energy of electrons, we found that the difference between them becomes larger for systems with rapidly changing density of states around the Fermi level, such as those with van Hove singularities in pressurized hydrides.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Article
Chemistry, Multidisciplinary
Jagdish Kumar, Harkirat Singh
Summary: Density functional theory (DFT) based ab-initio calculations were used to investigate the electronic, phononic, and superconducting properties of 1T-MoS2. The study revealed that the system exhibits electron-phonon mediated superconductivity, with the superconducting transition temperature slightly increasing under pressure before decreasing.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2021)
Article
Chemistry, Physical
Davide Romanin, Giovanni A. Ummarino, Erik Piatti
Summary: By performing calculations with parameters extracted from density functional theory simulations, we studied superconductivity in a 2-dimensional hole gas induced on the hydrogenated (111) diamond surface. It is possible to induce a high-Tc superconducting phase with a surface hole concentration of 6 x 10(14) cm(-2) across three valence bands. The use of multi-band calculations can enhance the critical temperature by approximately 4% to 8%.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Fabian Schrodi, Alex Aperis, Peter M. Oppeneer
Summary: The foundational theory of superconductivity by Eliashberg is based on Migdal's approximation, which neglects vertex corrections to lowest-order electron-phonon scattering if the ratio between phonon and electron energy scales is small. Full-bandwidth Eliashberg theory in two and three dimensions includes the full back reaction of electrons onto the phonon spectrum, revealing a complex interplay between various factors affecting superconductivity. Furthermore, a scaling law for the maximally possible critical temperature T-c(max) is proposed, which depends on the renormalized electron-phonon coupling strength and softened phonon spectrum in two- and three-dimensional systems.
Article
Nanoscience & Nanotechnology
Li-Qin Zhang, Jin-Feng Zhang, Li-Ming, Meng-Zheng Zhu, Shi-Tao Xu
Summary: The crystal structure, stability, and electron-phonon interactions of calcium dinitride (CaN2) have been studied by theoretical calculation, revealing that CaN2 has the potential to exhibit superconductivity. Pseudo-gaps were observed in the dispersion curves of CaN2 within a specific frequency range, indicating its possible superconducting behavior. Additionally, the superconducting temperature of CaN2 was found to be influenced by pressure, with an initial increase and subsequent decrease as the pressure rose.
SCIENCE OF ADVANCED MATERIALS
(2022)
Article
Multidisciplinary Sciences
Mir Mohammad Sadeghi, Yajie Huang, Chao Lian, Feliciano Giustino, Emanuel Tutuc, Allan H. MacDonald, Takashi Taniguchi, Kenji Watanabe, Li Shi
Summary: The peculiar electron-phonon interaction in graphene heterostructures enables ultrahigh mobility, electron hydrodynamics, superconductivity, and superfluidity. A peak in the Lorenz ratio near 60 kelvin and its decrease with increased mobility are observed in degenerate graphene, indicating an unusual behavior. This experimental observation, combined with ab initio calculations and analytical models, suggests that broken reflection symmetry in graphene heterostructures can relax the selection rule for electron coupling with flexural phonons, contributing to the increase of the Lorenz ratio at intermediate temperatures.
Article
Multidisciplinary Sciences
Ta Tang, Brian Moritz, Cheng Peng, Zhi-Xun Shen, Thomas P. Devereaux
Summary: This study demonstrates that extended electron-phonon coupling is a significant factor in generating the attractive coupling observed in one-dimensional cuprate materials, and can reproduce the spectral features and doping dependence seen in experiments.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Condensed Matter
Surinder Singh, Udomsilp Pinsook
Summary: Conventional superconducting parameters of La3In were calculated at ambient and applied positive hydrostatic pressure, including Eliashberg spectral function, phonon DOS, average electron-phonon coupling constant, and superconducting transition temperature. The results showed that the ambient pressure electron-phonon coupling constant was 1.43, and the superconducting transition temperature was calculated to be 8.7 K. Phonon dispersion relations were calculated to confirm the stability of La3In under positive pressure.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Chaopeng Zhao, Weishan Yan, Wangyang Zhang, Duo Liu
Summary: This study demonstrates that phonons can promote the relaxation of metastable centers in ZnO through the electron-phonon interaction. The findings provide valuable guidance for the development of novel quantum and photoactive devices.
Article
Chemistry, Multidisciplinary
Marten Duvel, Marco Merboldt, Jan Philipp Bange, Hannah Strauch, Michael Stellbrink, Klaus Pierz, Hans Werner Schumacher, Davood Momeni, Daniel Steil, G. S. Matthijs Jansen, Sabine Steil, Dino Novko, Stefan Mathias, Marcel Reutzel
Summary: This study investigates far-from-equilibrium many-body interactions using photoelectron spectroscopy and finds remarkable transient renormalizations of the quasiparticle self-energy due to non-equilibrium conditions. These observations can be explained by ultrafast scatterings between nonequilibrium electrons and strongly coupled optical phonons.
Article
Physics, Multidisciplinary
Abu Bakar, Muhammad Shahbaz, A. Afaq
Summary: The electronic, vibrational, and superconducting properties of B1-NbC were studied using a first-principles approach. Different density functional theory methods were employed, showing consistent electronic band structures but significant differences in phonon dispersion curves. Optical phonons contribute significantly to the electron-phonon coupling constant. The use of nonlocal functionals has a noticeable effect on the superconducting transition temperatures.
Article
Chemistry, Physical
Hyungjun Lee, Samuel Ponce, Kyle Bushick, Samad Hajinazar, Jon Lafuente-Bartolome, Joshua Leveillee, Chao Lian, Jae-Mo Lihm, Francesco Macheda, Hitoshi Mori, Hari Paudyal, Weng Hong Sio, Sabyasachi Tiwari, Marios Zacharias, Xiao Zhang, Nicola Bonini, Emmanouil Kioupakis, Elena R. Margine, Feliciano Giustino
Summary: EPW is an open-source software used for ab initio calculations of electron-phonon interactions and related materials properties. It efficiently computes electron-phonon coupling matrix elements and performs predictive calculations of temperature-dependent properties and phonon-assisted quantum processes. Recent developments include the addition of modules for calculating charge carrier mobility, phonon-mediated superconductivity, phonon-assisted indirect transitions, small and large polarons, and band structure renormalization. Examples and methodologies for each capability are provided.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Physics, Multidisciplinary
Yao Wang, Zhuoyu Chen, Tao Shi, Brian Moritz, Zhi-Xu Shen, Thomas P. Devereaux
Summary: This study establishes a minimal model for cuprates and highlights the crucial contribution of long-range electron-phonon coupling beyond standard Hubbard models. The research findings suggest a strong attractive interaction between neighboring electrons, comparable to experimental observations, due to nonlocal couplings mediating neighboring interactions. The structural and chemical similarities between 1D and 2D cuprate materials provide important insights for understanding cuprate high-Tc superconductivity and related quantum phases.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Jose D. Mella, Hernan L. Calvo, Luis E. F. Foa Torres
Summary: This report discusses the effects of electron-phonon interaction in materials, particularly in graphene. It shows that this interaction can lead to the formation of a gap bridged by unique edge states, with a distinctive locking among propagation direction, valley, and phonon mode. These findings shed light on how to utilize these unconventional states in quantum research.
Article
Materials Science, Multidisciplinary
Te-Huan Liu, Jiawei Zhou, Qian Xu, Xin Qian, Bai Song, Ronggui Yang
Summary: The study shows that long-range electron-phonon interaction can significantly suppress thermal conductivity in certain polar semiconductors by scattering acoustic phonons. The breaking of centrosymmetry has different effects on phonon transport in different crystal structures.
MATERIALS TODAY PHYSICS
(2022)
