发表机构
Technical University of Kenya（肯尼亚科技大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究提出宇称控制的激子-声子耦合干涉选择规则，揭示电子-空穴干涉对弗罗利希相互作用的调控机制，为设计定制化声子相互作用的激子材料提供通用判据。
AI 中文摘要
我们证实，极性半导体中的激子-声子耦合受宇称控制的干涉选择规则支配。通过对激子形状因子进行精确多极展开，并结合类氢包络函数的数值积分验证，我们发现对于相同宇称的激子态之间的弹性散射，弗罗利希（Fröhlich）相互作用的长程红外发散会被完全抵消。基态激子因此通过电子-空穴的相消干涉免受长波长极性声子的影响。相反，宇称相反的态之间的跃迁表现出相长干涉，保留了与宏观极性场的有限且稳健的耦合，且这种耦合与能带结构细节无关。电子与空穴的质量不对称会激活弹性通道中的高阶多极项，但对相长干涉的非弹性通道基本无影响。该选择规则具有维度不变性，同时适用于体材料和二维体系，可自然解释卤化物钙钛矿中观测到的异常弱声子修饰，以及过渡金属二硫化物中的强声子边带。我们的框架为激子-声子耦合强度提供了通用的解析精确判据，为设计具有定制化声子相互作用的激子材料提供了设计原理。
英文摘要
We demonstrate that exciton-phonon coupling in polar semiconductors is governed by a parity-controlled interference selection rule. By performing an exact multipole expansion of the excitonic form factor and validating it against numerical integration of hydrogenic envelope functions, we show that the long-range infrared divergence of the Fröhlich interaction is exactly canceled for elastic scattering between excitonic states of the same parity. The ground-state exciton is thereby protected from long-wavelength polar phonons by destructive electron-hole interference. In contrast, transitions between states of opposite parity exhibit constructive interference, preserving a finite, robust coupling to macroscopic polar fields independent of band-structure details. Mass asymmetry between the electron and hole activates higher-order multipole terms in the elastic channel but leaves the constructive inelastic channel essentially unaffected. The selection rule is dimensionally invariant, applying to bulk and two-dimensional systems alike, and naturally explains the anomalously weak phonon dressing observed in halide perovskites as well as the strong phonon sidebands in transition-metal dichalcogenides. Our framework provides a universal, analytically exact criterion for exciton-phonon coupling strength, offering a design principle for engineering excitonic materials with tailored phonon interactions.
Comments6 pages, 3 Figures, 2 tables
