Electron-Phonon Coupling & Beyond

My research centers on understanding how charge carriers interact with lattice vibrations in real materials — from first-principles polaron characterization to applying tensor cross interpolation (TCI) for many-body diagrammatic calculations of electron-phonon systems.

POLARON PHYSICS PH.D. PROJECT

Unveiling Asymmetric Polaron Formation in CeO₂

This work studied the fundamental physics of polarons in CeO₂, where I found the coexistence of two different polaron types in the same material: electrons form localized Holstein polarons, while holes form delocalized Fröhlich polarons. The results help clarify the microscopic carrier transport mechanisms and the roles of different phonon modes in limiting carrier mobility.

METHODOLOGY

DFT+U, Electron-Phonon Coupling

MATERIAL SYSTEM

CeO₂ (Ceria)

description View Publication
CeO₂ electron and hole polaron charge density

CeO₂ Polarons

Holstein vs. Fröhlich polaron coexistence

CRYSTAL SYMMETRY

Crystal Symmetry's Role in Polaron Transport

This project studied how crystal structure influences polaron behavior by systematically comparing three phases of BiVO₄ (monoclinic scheelite, tetragonal zircon-type, and tetragonal scheelite). Using ab initio calculations, we found that electron polarons consistently form as Holstein type, whereas hole polarons are of the Fröhlich type across all three structures. The analysis of dielectric tensors and Born effective charges revealed the microscopic origins of mobility differences, showing how crystal structure directly modulates polaron properties.

Crystal symmetry and polaron transport in BiVO₄
View Publication
MACRO-MESO MODELING star

Macro-Meso Modeling for Photoelectrode Design

This project built a continuity equation model fed by first-principles parameters to connect quantum mechanical calculations with device-level performance predictions. Using this approach, I estimated the optimal film thickness for p-type CuFeO₂ and explored the structural optimization of n-type Fe₂O₃ from thin films to nanowire arrays.

  • check_circle First-principles parameters → Device-level predictions
  • check_circle Optimized CuFeO₂ film thickness & Fe₂O₃ nanowire design
Photoelectrode band diagram — space charge region and continuity equation model
SCIENTIFIC SOFTWARE CORE DEVELOPER

CrystalCanvas

C++ (Eigen/Spglib) · wgpu · React/TS

Developing a hardware-accelerated desktop application for computational materials science, aiming to bridge the gap between crystal structure modeling and DFT/MD simulation preparations.

  • check_circle Physics Kernel: C++ engine for Miller index slab cleaving, space group topology evaluation, and MIC validation.
  • check_circle Native Rendering: GPU compute pipelines for real-time atomistic manipulation.
  • check_circle Ecosystem Integration: Exporters for VASP, Quantum ESPRESSO, and LAMMPS.
terminal GitHub Repository
SCIENTIFIC SOFTWARE CORE DEVELOPER

PolaronTCISolver

C++23 · Eigen · OpenMP · Tensor Train

A high-performance Tensor Cross Interpolation (TCI) engine for evaluating high-dimensional integrals and compressing multivariate functions into Tensor Train (TT) format. The library is designed for evaluating polaron Feynman diagrams, but the TCI engine itself is physics-agnostic — any function f : ℤN → ℝ with low Schmidt rank can be decomposed.

  • check_circle Zero-Allocation Hot Path: C++20 Concepts + std::mdspan out-parameter interface — zero new/delete in the solve loop.
  • check_circle CI Recompression: Cross-interpolation-based ‖·‖∞ truncation — superior to SVD for sharp features.
  • check_circle Deterministic Global Search: Halton QMC + fixed-seed MCMC + rook coordinate descent for robust pivot discovery.
  • check_circle Built-in Diagnostics: Pre-solve entanglement profiler (von Neumann entropy) + post-solve Monte Carlo convergence validator.

10D Chain-Coupled Lorentzian Demo

1610

grid points (~1.1 trillion)

530K

TT parameters

2M×

compression ratio

terminal Showcase Repository Full source available upon request for academic collaboration.
demo_tci

─── Entanglement Profiling ───

Max entropy: 0.1684

TCI feasible: ✅ Yes

···

─── TCI Learning ───

Status: ✅ Converged

Residual: 9.96e-07

···

─── TT Structure ───

Compression: 2,073,611×

Skills & Expertise

The computational tools and methods supporting my research.

PROGRAMMING

  • Python (NumPy, SciPy)
  • C++ (Eigen, STL)
  • Julia

SCIENTIFIC SOFTWARE

METHODS

  • Density Functional Theory
  • Electron-Phonon Coupling
  • Tensor Cross Interpolation
  • Polaron Theory

LANGUAGES

  • Chinese (Native)
  • English
Looking Ahead

Future Research Interests

Electron-Phonon Coupling in Strongly Correlated Systems

I hope to explore first-principles approaches for modeling EPC in strongly correlated materials. The interplay between strong electron-electron repulsion and lattice dynamics is relevant to understanding metal-insulator transitions and unconventional superconductivity.

Computational Design of Superconducting Materials

I am interested in studying phonon-mediated pairing mechanisms in different material families, including conventional superconductors under high pressure and unconventional systems, to better understand the conditions for higher transition temperatures.

Many-Body Methods for Polaron Systems

Building on recent advances in Quantics Tensor Cross Interpolation, I aim to extend TCI-based diagrammatic approaches to evaluate high-order Feynman diagrams for polaron systems in realistic multi-orbital materials, moving beyond model Hamiltonians toward first-principles accuracy.