arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.15196cond-mat.mes-hallcond-mat.mtrl-sci
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范德华异质结中与扭转角相关的层间激子寿命

Twist Angle Dependent Interlayer Exciton Lifetimes in van der Waals Heterostructures

Junho Choi, Matthias Florian, Alexander Steinhoff, Daniel Erben, Kha Tran, Dong Seob Kim, Liuyang Sun, Jiamin Quan, Robert Claassen, Somak Majumder, Jennifer A.… 展开作者

Junho Choi, Matthias Florian, Alexander Steinhoff, Daniel Erben, Kha Tran, Dong Seob Kim, Liuyang Sun, Jiamin Quan, Robert Claassen, Somak Majumder, Jennifer A. Hollingsworth, Takashi Taniguchi, Kenji Watanabe, Keiji Ueno, Akshay Singh, Galan Moody, Frank Jahnke, Xiaoqin Li

摘要:

在通过堆叠过渡金属二硫属化物的两个单层形成的范德华(vdW)异质结构中,形成具有高度可调谐性质的多个激子共振,并且受到垂直和横向限制。我们研究如何一个独特的控制旋钮,两个单层之间的扭曲角,可以用来控制激子动力学。我们观察到当扭转角从1 $^\circ$变化到3.5 $^\circ$时,$\text{MoSe}_{\text{2}}$ / $\text{WSe}_{\text{2}}$扭转双层膜(TBL)的层间激子寿命变化了一个数量级.使用低能量连续模型,我们从理论上分离两个主要的机制,影响层间激子辐射寿命。随着扭转角的增加,动量空间向间接跃迁的转变以及来自莫尔势的能量调制都对层间激子寿命有显著影响。我们进一步预测了不同扭转角的TBL层间激子寿命随温度的变化关系,并得到了部分实验验证。虽然最近的许多研究已经强调了如何在VDW TBL的扭曲角可以被用来工程的基态和量子相位由于多体相互作用,我们的研究探索其在控制光学激发态的动力学的作用,从而扩大了“twistronics”的概念应用。

英文摘要:

In van der Waals (vdW) heterostructures formed by stacking two monolayers of transition metal dichalcogenides, multiple exciton resonances with highly tunable properties are formed and subject to both vertical and lateral confinement. We investigate how a unique control knob, the twist angle between the two monolayers, can be used to control the exciton dynamics. We observe that the interlayer exciton lifetimes in $\text{MoSe}_{\text{2}}$/$\text{WSe}_{\text{2}}$ twisted bilayers (TBLs) change by one order of magnitude when the twist angle is varied from 1$^\circ$ to 3.5$^\circ$. Using a low-energy continuum model, we theoretically separate two leading mechanisms that influence interlayer exciton radiative lifetimes. The shift to indirect transitions in the momentum space with an increasing twist angle and the energy modulation from the moiré potential both have a significant impact on interlayer exciton lifetimes. We further predict distinct temperature dependence of interlayer exciton lifetimes in TBLs with different twist angles, which is partially validated by experiments. While many recent studies have highlighted how the twist angle in a vdW TBL can be used to engineer the ground states and quantum phases due to many-body interaction, our studies explore its role in controlling the dynamics of optically excited states, thus, expanding the conceptual applications of "twistronics".

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。

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