The interplay between exctions and vibrations is considered to be a key factor in determining the exciton transfer properties in light-harvesting exciton transfer complexes. Here we study this interplay theoretically in a model for exciton transport, composed of two chromophores coupled to an exciton source and sink in the presence of vibrations. We consider two cases, that show qualitatively distinct transport features. In the first, the vibrations are global and affect the two chromophores simultaneously. In the second case, the vibrations are localized on each chromophore. For global vibrations, the current exhibits {\sl anti-resonances} as a function of the chromophore energy difference, which are due to exciton-polaron interference. For local vibrations, on the other hand, the currents shows tunneling {\sl resonances} at multiples of the vibration energy. Counter-intuitively, both effects increase with increasing temperature. Our results demonstrate that an environment can either assist or hamper exciton transport, and are in accord with current understanding of energy transfer in natural exciton transfer complexes.
The dark side of energy transport along excitonic wires: On-site energy barriers facilitate efficient, vibrationally-mediated transport through optically dark subspaces
Excitonic and vibronic spectra of Frenkel excitons in a two-dimensional simple latice
研究了二维单分子晶格中Frenkel激子的激子和振动谱,并模拟了它们在线性吸收中的表现。我们使用格林函数形式主义,振动方法(参见Lalov和Zhelyazkov [Phys. Rev. B \textbf{75},245435(2007)]),以及最近邻近似以找到闭合形式的线性吸收线型的表达式(根据椭圆积分)对于以下2D模型:(a)聚并苯的振动光谱(萘、蒽、并四苯);(b)简单六方晶格的振动光谱。这两个二维模型包括线性和二次FE-声子耦合。我们的模拟涉及激子态密度(DOS),以及振动光谱(FE加一个声子,FE加两个声子)的位置和线形。多粒子(MP-未绑定)FE-声子态的位置,以及范霍夫奇异性对线性吸收的影响已经建立通过使用激子和振动参数的典型值。在一个简单的六边形晶格的情况下,以下类型的FE已被认为是:(i)非简并FE的过渡偶极矩是垂直于晶格的平面,和(ii)简并FE的过渡偶极矩平行于层。我们发现了一个累积的影响的线性和二次FE-声子耦合的振动极大值的位置的情况下(ii),和补偿的情况下(i)的影响。
Layer-Dependent Phonons, Excitons, and Magneto-Optical Phenomena in CrSBr: A Mini Review
National Center for Nanoscience and Technology(中国科学院国家纳米科学中心);University of Chinese Academy of Sciences(中国科学院大学);University of Warsaw(华沙大学);CNRS–UGA–UPS–INSA–EMFL(法国国家科学研究中心-格勒诺布尔阿尔卑斯大学-图卢兹第三大学-INSA图卢兹-东洛林大学);University of Sapienza(罗马第一大学)
Exciton-Phonon Coupling and Band-Gap Renormalization in Monolayer WSe$_{2}$
使用一个完全从头算方法,我们演示了如何晶格振动与单层WSe 2中的中性激子耦合,并有助于非辐射激子寿命。我们表明,只有同时处理电子-电子和电子-声子相互作用,才有可能获得与实验结果空前一致的零温和有限温光学带隙和吸收谱。裸能通过求解Kohn-Sham方程计算,而激发态能则采用G $_{0}$ W $_{0}$多体微扰理论计算.结合极化子能量求解了耦合的电子-空穴Bethe-Salpeter方程,表明面内扭转声学声子分支对A和B激子的建立贡献最大。我们发现,三个A,B和C激子峰表现出不同的行为与温度,显示不同的非辐射线宽。激子的强度随温度的变化没有明显的变化,但A激子比C激子具有更暗的性质。此外,所有激子峰随着温度升高而红移。声子相互作用和非谐晶格热膨胀对裸电子能量的重整化导致带隙随温度的升高而减小。零点能量重整化(31毫电子伏)被认为是完全由于极化相互作用与晶格非谐的贡献可以忽略不计。这些发现可能会对基于这些单层的电子和光电子器件技术产生深远的影响。
Moiré Phonons and Emergent Exciton-Phonon Coupling in a Moiré Heterobilayer
University of California, Berkeley(加州大学伯克利分校);Kavli Energy NanoScience Institute(卡弗里能源纳米科学研究所);Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室);Indian Institute of Science(印度科学学院);Newcastle University(纽卡斯尔大学);National Institute for Materials Science(国立材料研究所);University of Texas at Austin(德克萨斯大学奥斯汀分校);Northeastern University(东北大学)