Phonon Screening of Excitons in Semiconductors: Halide Perovskites and Beyond,Physical Review Letters

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Phonon Screening of Excitons in Semiconductors: Halide Perovskites and Beyond
Physical Review Letters ( IF 8.1 ) Pub Date : 2021-08-05 , DOI: 10.1103/physrevlett.127.067401
Marina R Filip _{1,

2,

3} , Jonah B Haber ₂ , Jeffrey B Neaton _{2,

4,

5}

Affiliation

The ab initio Bethe-Salpeter equation (BSE) approach, an established method for the study of excitons in materials, is typically solved in a limit where only static screening from electrons is captured. Here, we generalize this framework to include dynamical screening from phonons at lowest order in the electron-phonon interaction. We apply this generalized BSE approach to a series of inorganic lead halide perovskites,

CsPb X_{3}

, with

X = Cl

, Br, and I. We find that inclusion of screening from phonons significantly reduces the computed exciton binding energies of these systems. By deriving a simple expression for phonon screening effects, we reveal general trends for their importance in semiconductors and insulators, based on a hydrogenic exciton model. We demonstrate that the magnitude of the phonon screening correction in isotropic materials can be reliably predicted using four material specific parameters: the reduced effective mass, static and optical dielectric constants, and frequency of the most strongly coupled longitudinal-optical phonon mode. This framework helps to elucidate the importance of phonon screening and its relation to excitonic properties in a broad class of semiconductors.

中文翻译：

半导体中激子的声子筛选：卤化物钙钛矿及其他

在从头贝特-萨尔皮特方程（BSE）的方法，用于激子在材料研究中已建立的方法，典型地解决了在仅由电子静态筛选被捕获的限制。在这里，我们将这个框架概括为包括对电子-声子相互作用中最低阶声子的动态筛选。我们将这种广义 BSE 方法应用于一系列无机卤化铅钙钛矿，

铅铅 十_{3}

, 与

十 = 氯

、Br 和 I。我们发现包含声子屏蔽显着降低了这些系统的计算激子结合能。通过推导出声子屏蔽效应的简单表达式，我们基于氢激子模型揭示了它们在半导体和绝缘体中的重要性的一般趋势。我们证明了可以使用四个特定于材料的参数可靠地预测各向同性材料中声子屏蔽校正的幅度：减少的有效质量、静态和光学介电常数以及最强耦合纵向光学声子模式的频率。该框架有助于阐明声子屏蔽的重要性及其与一大类半导体中激子特性的关系。

更新日期：2021-08-05

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