Stark shift of excitons and trions in two-dimensional materials
Stark shift of excitons and trions in two-dimensional materials
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DOI：
10.1103/physrevb.98.245309
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发表时间：
2018-12-20
影响因子：
3.7
通讯作者：
Chaves, A.
中科院分区：
文献类型：
--
作者：
Cavalcante, L. S. R.;da Costa, D. R.;Chaves, A.
从理论上研究了平面外电场对二维材料中中性和带电激子态的影响。这些状态被认为是强束缚的，因此在高电场强度下，电子-空穴解离不会被观察到。在各向异性情况下，单层磷二烯的三角子在电场作用下表现出特别强的鲁棒性，因此高达100 kV/cm的电场对三角子的结合能和概率密度分布没有显著影响。激子的极化率由数值计算的斯塔克位移的抛物线性得到。对于trions，观察到四阶Stark位移，这使得实验验证二维材料中的超极化性，正如在Rydberg系列原子和离子的高激发态中观察到的那样。
The effect of an external in-plane electric field on neutral and charged exciton states in two-dimensional (2D) materials is theoretically investigated. These states are argued to be strongly bound, so that electron-hole dissociation is not observed up to high electric field intensities. Trions in the anisotropic case of monolayer phosphorene are demonstrated to be especially robust under electric fields, so that fields as high as 100 kV/cm yield no significant effect on the trion binding energy or probability density distribution. Polarizabilities of excitons are obtained from the parabolicity of numerically calculated Stark shifts. For trions, a fourth order Stark shift is observed, which enables the experimental verification of hyperpolarizability in 2D materials, as observed in the highly excited states of the Rydberg series of atoms and ions.