近日，中国科学技术大学赵瑾团队研究了二维过渡金属二硫族化合物中激子电子-空穴复合的多体增强。这一研究成果发表在2026年1月13日出版的《中国物理快报》杂志上。

电子-空穴复合是决定半导体能量耗散与器件效率的基础过程。在二维材料中，强束缚激子的形成使激子介导的电子-空穴复合成为主要衰变途径。

研究组采用结合非绝热分子动力学与GW近似、实时贝特-萨尔佩特方程传播的第一性原理模拟方法，对单层二硫化钼中激子的非辐射电子-空穴复合过程进行了研究。发现该过程包含两个步骤：首先由交换相互作用诱导快速的谷间再分布，随后激子结合作用促进较慢的声子辅助复合。

通过选择性移除贝特-萨尔佩特方程哈密顿量中的屏蔽库仑项与交换项，研究组厘清了二者的各自贡献——交换相互作用可增加可及复合路径的数量，而激子结合作用则通过降低激发能增强非辐射衰变。由于激子多体效应，复合寿命被观测到缩短超过一个数量级。这些发现为理解和调控二维过渡金属硫族化物中的激子寿命提供了微观机制理解。

附：英文原文

Title: Many-Body Enhancement of Excitonic Electron-Hole Recombination in Two-Dimensional Transition Metal Dichalcogenides

Author: Li Yao, Xiang Jiang, Qijing Zheng, Jin Zhao

Issue&Volume: 2026-01-13

Abstract: Electron-hole (e-h) recombination is a fundamental process that governs energy dissipation and device efficiency in semiconductors. In two-dimensional (2D) materials, the formation of tightly bound excitons makes exciton-mediated e-h recombination the dominant decay pathway. In this work, nonradiative e-h recombination within excitons in monolayer MoS2 is investigated using first-principles simulations that combine nonadiabatic molecular dynamics with GW and real-time Bethe-Salpeter equation (BSE) propagation. A two-step process is identified: rapid intervalley redistribution induced by exchange interaction, followed by slower phonon-assisted recombination facilitated by exciton binding. By selectively removing the screened Coulomb and exchange terms from the BSE Hamiltonian, their respective contributions are disentangled—exchange interaction is found to increase the number of accessible recombination pathways, while binding reduces the excitation energy and enhances nonradiative decay. A reduction in recombination lifetime by over an order of magnitude is observed due to the excitonic many-body effects. These findings provide microscopic insights for understanding and tuning exciton lifetimes in 2D transition-metal dichalcogenides.

DOI: 10.1088/0256-307X/43/1/010701

Source: https://cpl.iphy.ac.cn/article/doi/10.1088/0256-307X/43/1/010701