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Electronic Origin of Optically-Induced Sub-Picosecond Lattice Dynamics in MoSe2 Monolayer
Nano Letters ( IF 9.6 ) Pub Date : 2018-07-10 00:00:00 , DOI: 10.1021/acs.nanolett.8b00474 Lindsay Bassman , Aravind Krishnamoorthy , Hiroyuki Kumazoe 1 , Masaaki Misawa 1 , Fuyuki Shimojo 1 , Rajiv K. Kalia , Aiichiro Nakano , Priya Vashishta
Nano Letters ( IF 9.6 ) Pub Date : 2018-07-10 00:00:00 , DOI: 10.1021/acs.nanolett.8b00474 Lindsay Bassman , Aravind Krishnamoorthy , Hiroyuki Kumazoe 1 , Masaaki Misawa 1 , Fuyuki Shimojo 1 , Rajiv K. Kalia , Aiichiro Nakano , Priya Vashishta
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Atomically thin layers of transition metal dichalcogenide (TMDC) semiconductors exhibit outstanding electronic and optical properties, with numerous applications such as valleytronics. While unusually rapid and efficient transfer of photoexcitation energy to atomic vibrations was found in recent experiments, its electronic origin remains unknown. Here, we study the lattice dynamics induced by electronic excitation in a model TMDC monolayer, MoSe2, using nonadiabatic quantum molecular dynamics simulations. Simulation results show sub-picosecond disordering of the lattice upon photoexcitation, as measured by the Debye–Waller factor, as well as increasing disorder for higher densities of photogenerated electron–hole pairs. Detailed analysis shows that the rapid, photoinduced lattice dynamics are due to phonon-mode softening, which in turn arises from electronic Fermi surface nesting. Such mechanistic understanding can help guide optical control of material properties for functionalizing TMDC layers, enabling emerging applications such as phase change memories and neuromorphic computing.
中文翻译：
MoSe 2单层中光诱导的亚皮秒晶格动力学的电子起源
过渡金属二硫化氢（TMDC）半导体的原子薄层具有出色的电子和光学特性，具有许多应用，例如Valleytronics。尽管在最近的实验中发现了光激发能量异常快速有效地转移到原子振动上，但其电子起源仍然未知。在这里，我们研究了模型TMDC单层MoSe 2中由电子激发引起的晶格动力学。，使用非绝热量子分子动力学模拟。模拟结果表明，通过德拜-沃勒因子测得的光激发时，晶格处于亚皮秒级的无序状态，并且随着光生电子-空穴对密度的增加，无序状态也会增加。详细的分析表明，快速的光诱导晶格动力学归因于声子模式软化，而声子模式软化又源于电子费米表面嵌套。这种机械的理解可以帮助指导对材料特性进行光学控制，以使TMDC层功能化，从而实现诸如相变存储器和神经形态计算等新兴应用。
更新日期：2018-07-10
中文翻译：
MoSe 2单层中光诱导的亚皮秒晶格动力学的电子起源
过渡金属二硫化氢（TMDC）半导体的原子薄层具有出色的电子和光学特性，具有许多应用，例如Valleytronics。尽管在最近的实验中发现了光激发能量异常快速有效地转移到原子振动上，但其电子起源仍然未知。在这里，我们研究了模型TMDC单层MoSe 2中由电子激发引起的晶格动力学。，使用非绝热量子分子动力学模拟。模拟结果表明，通过德拜-沃勒因子测得的光激发时，晶格处于亚皮秒级的无序状态，并且随着光生电子-空穴对密度的增加，无序状态也会增加。详细的分析表明，快速的光诱导晶格动力学归因于声子模式软化，而声子模式软化又源于电子费米表面嵌套。这种机械的理解可以帮助指导对材料特性进行光学控制，以使TMDC层功能化，从而实现诸如相变存储器和神经形态计算等新兴应用。
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