arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.10795cond-mat.mes-hall
收藏

与腔强耦合的分子晶体中激子输运理论:温度相关的变分法

Theory of exciton transport in molecular crystals strongly coupled to a cavity: A temperature-dependent variational approach

Jingyu Liu, Qing Zhao, Ning Wu

摘要:

本文提出了有机分子晶体中激子输运的半解析理论。基于Holstein-Tavis-Cummings模型和Kubo公式,我们在温度依赖的变分正则变换框架下推导出激子迁移率表达式,该表达式可以涵盖激子-振动耦合、激子-腔耦合和温度的广泛范围.在激子-振动耦合的零阶中得到了总迁移率相干部分的封闭形式的表达式,这表明了振动修饰暗激子在确定输运机制中的意义。通过对H-和J-聚集体的数值模拟,我们发现激子-腔耦合对总迁移率有显著的影响:1)在低温下,H-聚集体存在一个最佳激子-腔耦合强度,在此强度下迁移率达到最大,而J-聚集体的迁移率随着激子-腔耦合的增加而单调下降; 2)在高温下,空穴增强了两种团聚体的流动性。我们说明了上述低温下观察到的H-聚集体中的最佳流动性在室温下使用现实的参数。

英文摘要:

We present a semianalytical theory for exciton transport in organic molecular crystals interacting strongly with a single cavity mode. Based on the Holstein-Tavis-Cummings model and the Kubo formula, we derive an exciton mobility expression in the framework of a temperature-dependent variational canonical transformation, which can cover a wide range of exciton-vibration coupling, exciton-cavity coupling, and temperatures. A closed-form expression for the coherent part of the total mobility is obtained in the zeroth order of the exciton-vibration coupling, which demonstrates the significance of vibrationally dressed dark excitons in the determination of the transport mechanism. By performing numerical simulations on both the H- and J-aggregates, we find that the exciton-cavity coupling has significant effects on the total mobility: 1) At low temperatures, there exists an optimal exciton-cavity coupling strength for the H-aggregate at which a maximal mobility is reached, while the mobility in the J-aggregate decreases monotonically with increasing exciton-cavity coupling; 2) At high temperatures, the mobility in both types of aggregates get enhanced by the cavity. We illustrate the above-mentioned low-temperature optimal mobility observed in the H-aggregate by using realistic parameters at room temperature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑