Fermi Pressure and Coulomb Repulsion Driven Rapid Hot Plasma Expansion in a van der Waals Heterostructure
Fermi Pressure and Coulomb Repulsion Driven Rapid Hot Plasma Expansion in a van der Waals Heterostructure
复制标题
DOI：
10.1021/acs.nanolett.3c00678
复制
发表时间：
2023-05-08
期刊：
影响因子：
10.8
通讯作者：
Huang, Libai
中科院分区：
文献类型：
--
作者：
Choi, Junho;Embley, Jacob;Huang, Libai
过渡金属二硫属化物异质结构提供了一个多功能的平台，探索电子和激子相。当激发密度超过临界Mott密度时，层间激子被电离成电子-空穴等离子体相。高度非平衡等离子体的传输与高功率光电器件有关，但以前没有仔细研究过。在这里，我们采用空间分辨泵浦-探测显微镜研究MoSe 2/WSe 2扭曲双层中层间激子和热等离子体相的时空动力学。在激发密度接近10（14）cm（-2），远远超过Mott密度时，我们发现热等离子体在0.2 ps内惊人地迅速膨胀到离激发源几微米远的地方。微观理论表明，这种快速膨胀主要是由费米压力和库仑排斥驱动的，而热载流子效应在等离子体相中只有很小的影响。
Transition metal dichalcogenide heterostructures provide a versatile platform to explore electronic and excitonic phases. As the excitation density exceeds the critical Mott density, interlayer excitons are ionized into an electron-hole plasma phase. The transport of the highly non-equilibrium plasma is relevant for high-power optoelectronic devices but has not been carefully investigated previously. Here, we employ spatially resolved pump-probe microscopy to investigate the spatial-temporal dynamics of interlayer excitons and hot-plasma phase in a MoSe2/WSe2 twisted bilayer. At the excitation density of similar to 10(14) cm(-2), well exceeding the Mott density, we find a surprisingly rapid initial expansion of hot plasma to a few microns away from the excitation source within similar to 0.2 ps. Microscopic theory reveals that this rapid expansion is mainly driven by Fermi pressure and Coulomb repulsion, while the hot carrier effect has only a minor effect in the plasma phase.