长程交换相互作用控制半导体量子点中激发三激子态的精细结构
Long-range exchange interaction controls the fine structure of excited trion states in semiconductor quantum dots
浏览论文内容
中文总结 AI 辅助
该研究建立了半导体量子点中带电激子的电子-空穴长程交换相互作用微观理论，推导了对应模型的哈密顿量，解释了激发三激子的精细结构及偏振相关光谱，为相关光谱解读提供了框架。
中文摘要 AI 辅助
我们建立了半导体量子点中受限的带电激子（三激子）内电子-空穴长程交换相互作用的微观理论。尽管基态单重态三激子因时间反演对称性，未配对电荷载流子的自旋分量保持简并，但激发三激子态因电子-电子与电子-空穴交换相互作用的耦合呈现出丰富的精细结构。我们针对自旋-3/2重空穴模型和简单的自旋-1/2价带模型，推导了长程交换有效哈密顿量。长程交换相互作用会混合单重态与三重态三激子构型，产生由量子点形状决定的各向异性精细结构分裂及相关偏振依赖光学谱；我们还得到了长程交换参数的解析表达式。该理论为半导体量子点中激发三激子的精细结构建立了统一的微观描述，为解读带电激子复合物的偏振分辨光学光谱提供了框架。
英文摘要
We develop a microscopic theory of the long-range electron-hole exchange interaction in charged excitons (trions) confined in semiconductor quantum dots. While the ground-state singlet trion remains degenerate in the spin component of unpaired charge carrier by time-reversal symmetry, excited trion states exhibit a rich fine structure resulting from the interplay of electron-electron and electron-hole exchange interactions. We derive the effective long-range exchange Hamiltonian for both the spin-$3/2$ heavy-hole and a simple spin-$1/2$ valence band models. The long-range exchange interaction mixes singlet and triplet trion configurations, giving rise to anisotropic fine-structure splittings and related polarization-dependent optical spectra determined by the quantum-dot shape. Analytical expressions are obtained for the long-range exchange parameters. The developed theory establishes a unified microscopic description of the fine structure of excited trions in semiconductor quantum dots and provides a framework for interpreting polarization-resolved optical spectroscopy of charged excitonic complexes.
