Phonon Dephasing Dynamics in MoS 2
Phonon Dephasing Dynamics in MoS 2
复制标题
MoS 2 中的声子相移动力学
DOI：
10.1021/acs.nanolett.0c04368
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发表时间：
2021
期刊：
影响因子：
10.8
通讯作者：
Chang, Yu-Ming
中科院分区：
文献类型：
--
作者：
Sun, Liuyang;Kumar, Parveen;Liu, Zeyu;Choi, Junho;Fang, Bin;Roesch, Sebastian;Tran, Kha;Casara, Joshua;Priego, Eduardo;Chang, Yu-Ming
各种量子自由度，例如，在原子级薄的货车德瓦耳斯材料中的自旋、谷和定域发射体已经被提出用于量子信息应用，并且它们不可避免地耦合到声子。在这里，我们直接测量的内禀光学声子退相干在单层和散装MoS2通过观察的时间演化的光谱干涉的斯托克斯光子产生的激光脉冲对。我们发现，一个突出的光学声子模式E2g表现出室温下的退相时间为10.7 ps的单层和散装。这种退相时间在15K下在大块晶体中延伸到120 ps，这比以前认为的可能要长。第一性原理计算表明，光学声子通过两种类型的三声子过程衰减，其中产生一对动量相反的声学声子。
A variety of quantum degrees of freedom, e.g., spins, valleys, and localized emitters, in atomically thin van der Waals materials have been proposed for quantum information applications, and they inevitably couple to phonons. Here, we directly measure the intrinsic optical phonon decoherence in monolayer and bulk MoS2by observing the temporal evolution of the spectral interference of Stokes photons generated by pairs of laser pulses. We find that a prominent optical phonon mode E2gexhibits a room-temperature dephasing time of ∼7 ps in both the monolayer and bulk. This dephasing time extends to ∼20 ps in the bulk crystal at ∼15 K, which is longer than previously thought possible. First-principles calculations suggest that optical phonons decay via two types of three-phonon processes, in which a pair of acoustic phonons with opposite momentum are generated.