Deep neural network for phonon-assisted optical spectra of semiconductors at finite temperatures
摘要
Simulating phonon-assisted optical spectra in semiconductors at finite temperatures presents a classic accuracy-efficiency dilemma: thermodynamic configurational sampling requires large supercells, while accurate electronic properties demand expensive exchange-correlation (XC) functionals. In this work, we present a machine learning workflow that integrates deep learning potentials (DeePMD) with tight-binding (DeePTB) models to overcome this bottleneck. This approach enables non-perturbative treatment of finite-temperature structural sampling and configuration-dependent electronic evaluation within the Born-Oppenheimer (BO) approximation. By confining expensive Heyd-Scuseria-Ernzerhof (HSE) calculations to small cells and transferring the trained Hamiltonian to supercells of up to 4096 atoms, we achieve large-scale simulations of temperature-dependent optical properties without empirical corrections. We validate this framework by modeling phonon-induced bandgap renormalization and direct/indirect absorption in mainly two classes of materials: non-polar Si, weakly-polar GaAs, and GaP (100-400 K). Our findings are in excellent agreement with experiments. This method enables high-fidelity ab initio simulation of electron-ion-coupled phenomena in this wide class of materials at previously inaccessible scales.