CAREER:Coupling Between Correlated Electrons and Phonons from First Principles

项目来源

美国国家科学基金(NSF)

项目主持人

Zhenglu Li

项目受资助机构

UNIVERSITY OF SOUTHERN CALIFORNIA

项目编号

2440763

立项年度

2025

立项时间

未公开

项目级别

国家级

研究期限

未知 / 未知

受资助金额

238000.00美元

学科

未公开

学科代码

未公开

基金类别

Continuing grant

关键词

CONDENSED MATTER&MAT THEORY ; CAREER-Faculty Erly Career Dev ; CYBERINFRASTRUCTURE/SCIENCE ; CDS&E ; Clean Energy Technology ; Energy Storage or Transmission ; ADVANCED SOFTWARE TECH&ALGOR

参与者

未公开

参与机构

UNIVERSITY OF SOUTHERN CALIFORNIA

项目标书摘要:NONTECHNICAL SUMMARYThis award supports research,education,and outreach activities focused on understanding materials properties driven by the coupling between electrons and the vibrations of atom lattices in solids.This electron-lattice vibration interaction is fundamental to many phenomena,such as electric heating in transistors,light absorption and energy conversion in solar cells,and superconductivity where electric current is conducted with zero loss.The theoretical understanding of these phenomena can be simplified by considering electrons as independent of each other and considering their coupling to the lattice vibrations individually.However,in many topical materials of technological significance,electrons interact strongly among themselves while also collectively coupled to the lattice vibrations.Such strong interaction and coupling leads to exotic quantum phenomena,but it also presents challenges in achieving a clear understanding of the behaviors of such materials.This project addresses these challenges by developing and applying advanced quantum-mechanical computational approaches and large-scale simulation techniques.The goal of this research is to reveal the actual role of electron-lattice vibration coupling in interacting-electron materials systems and to explain intricate phenomena observed in novel superconductors and semiconductors.This project supports the education of a graduate student.Additionally,the project integrates research,community building,education,and outreach activities,by targeting a wide range of researchers,from high-school students to undergraduate students,to graduate students,and postdoctoral researchers.The PI will provide summer internship positions for high-school and undergraduate students and design appropriate research training projects.This project will also support various tutorial workshops to promote advanced computational methods for the young generations and foster collaborations in the scientific community.TECHNICAL SUMMARYThis award supports research,education,and outreach activities focused on studying the interaction between phonons and many-body correlated electrons,and the role of electron-phonon coupling in driving exotic phases in and out of equilibrium.The understanding remains elusive largely due to the lack of appropriate ab initio methodologies that treat electron-electron and electron-phonon interactions at the many-body level simultaneously.This project will use newly developed many-body approaches,namely GW perturbation theory and time-dependent adiabatic GW with phonons(where G represents the single-particle Green function and W is the screened Coulomb interaction),to(i)address the role of phonons in unconventional and novel superconductors,and(ii)investigate many-body self-energy effects and nonequilibrium dynamics in phonon-assisted optical phenomena in semiconductors.This project will push forward the ab initio electron-phonon coupling computation into the many-electron level and the nonequilibrium regime,vastly expanding the application scope of many-body perturbation theory to phonon-relevant phenomena.This project integrates research,community building,education,and outreach activities to expose a broad range of generations of students and researchers to various computational and theoretical techniques and scientific advancements.This project will promote novel electron-phonon coupling computational approaches through pilot workshops and foster coherent collaborations among software developers and users.The PI will provide summer internship positions for high-school and undergraduate students via designed outreach and education activities to introduce frontier materials and physics research progress,and to prepare young generations to pursue future careers in science and engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

人员信息

Zhenglu Li(Principal Investigator):zhenglul@usc.edu;

机构信息

【University of Southern California(Performance Institution)】StreetAddress:3651 Watt Way.VHE 508,LOS ANGELES,California,United States/ZipCode:900891211;【UNIVERSITY OF SOUTHERN CALIFORNIA】StreetAddress:3720 S FLOWER ST FL 3,LOS ANGELES,California,United States/PhoneNumber:2137407762/ZipCode:90033;

项目主管部门

Directorate for Mathematical and Physical Sciences(MPS)-Division Of Materials Research(DMR)

项目官员

Serdar Ogut(Email:sogut@nsf.gov;Phone:7032924429)

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  • 1.ISOME: Streamlining high-precision Eliashberg calculations

    • 关键词:
    • Approximation theory;Coulomb interactions;Cutoff frequency;Electronic density of states;Fermi level;Organic superconducting materials;Constant density;Densities of state;Eliashberg theory;Energy dependent;High-precision;High-throughput;Machine-learning;Matsubara frequency;Superconducting properties;Superconducting temperatures
    • Kogler, Eva;Spath, Dominik;Lucrezi, Roman;Mori, Hitoshi;Zhu, Zien;Li, Zhenglu;Margine, Elena R.;Heil, Christoph
    • 《Computer Physics Communications》
    • 2025年
    • 315卷
    • 期刊

    This paper introduces the Julia package ISOME, an easy-to-use yet accurate and robust computational tool designed to calculate superconducting properties. Multiple levels of approximation are supported, ranging from the basic McMillan-Allen-Dynes formula and its machine learning-enhanced variant to Eliashberg theory, including static Coulomb interactions derived from GW calculations, offering a fully ab initio approach to determine superconducting properties, such as the critical superconducting temperature (Tc) and the superconducting gap function (Δ). We validate ISOME by benchmarking it against various materials, demonstrating its versatility and performance across different theoretical levels. The findings indicate that the previously held assumption that Eliashberg theory overestimates Tc is no longer valid when μ⁎ is appropriately adjusted to account for the finite Matsubara frequency cutoff. Furthermore, we conclude that the constant density of states (DOS) approximation remains accurate in most cases. By unifying multiple approximation schemes within a single framework, ISOME combines first-principles precision with computational efficiency, enabling seamless integration into high-throughput workflows through its Tc search mode. This makes ISOME a powerful and reliable tool for advancing superconductivity research. Program summary: Program Title: ISOME CPC Library link to program files: https://doi.org/10.17632/frwsdxf44s.1 Developer's repository link: https://github.com/cheil/IsoME.jl Licensing provisions: MIT license Programming language: Julia 1.10 or higher Supplementary material: https://cheil.github.io/IsoME.jl Nature of problem: The challenge addressed by ISOME is the rigorous, first-principles calculation of superconducting properties, particularly the critical temperature (Tc) and detailed self-energy components. Predicting these properties involves solving the highly nonlinear, coupled Migdal-Eliashberg equations that capture the interplay between electron-phonon interactions and Coulomb repulsion. This is nontrivial because the equations require careful treatment of frequency-dependent interactions, accurate sampling of the electronic density of states near the Fermi level, and efficient summation over extensive Matsubara frequencies. Additionally, incorporating energy-dependent screening effects and ensuring numerical convergence across multiple energy scales further complicates the task. Addressing these issues is essential not only for understanding the fundamental physics of superconductivity but also for guiding the discovery and design of new superconducting materials. Solution method: ISOME employs isotropic Migdal-Eliashberg theory as its backbone, implementing a hierarchical approach that spans several levels of approximation. At the simplest level, the code uses semi-empirical formulas such as the McMillan-Allen-Dynes equation enhanced by machine learning to provide quick estimates of Tc. For more detailed studies, it solves self-consistently the full set of Eliashberg equations using either a constant or variable density of states (DOS) approximation, with the possibility to include the full energy-dependent static Coulomb interaction computed via GW methods. The package is written in Julia, ensuring high computational efficiency and ease of integration into high-throughput workflows. It further incorporates sparse-sampling techniques to accelerate Matsubara frequency summations and an automated Tc search mode, thereby balancing computational cost with high-precision predictions. Additional comments including restrictions and unusual features: ISOME is an open-source Julia package designed for high-throughput superconductivity investigations. Its modular architecture supports diverse approximation schemes that balance efficiency and accuracy. However, robust predictions require high-quality input data and thorough convergence testing, particularly for systems with complex electronic structures or strong energy-dependent interactions near the Fermi level. © 2025 The Author(s)

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