论文标题

单层半导体中相互作用载体的自发谷极化

Spontaneous valley polarization of interacting carriers in a monolayer semiconductor

论文作者

Li, Jing, Goryca, Mateusz, Wilson, Nathan P., Stier, Andreas V., Xu, Xiaodong, Crooker, Scott A.

论文摘要

我们报告了高磁场的封闭式WSE $ _2 $单层的磁性吸收光谱,最高为60〜t。当用2D费米海洋的移动孔掺杂时,在$σ^\ pm $圆极化中都观察到了精确的光学转换序列,这些循环循环循环循环循环,这些循环循环的圆极化均明确和单独地指出了$ k $和$ k'$ k'ub valleys中填充的Landau级别(LLS)的数量。这揭示了相互作用增强的山谷Zeeman Energy,发现孔密度$ P $非常可调。我们利用这种可调节性将LLS与$ k $和$ k'$保持一致,并发现2D孔气体对LL填充的微小变化变得不稳定,并且可以自发地极化山谷。这些结果在单粒子图片中无法理解,这突出了交换相互作用在确定单层半导体中2D载体基态的重要性。

We report magneto-absorption spectroscopy of gated WSe$_2$ monolayers in high magnetic fields up to 60~T. When doped with a 2D Fermi sea of mobile holes, well-resolved sequences of optical transitions are observed in both $σ^\pm$ circular polarizations, which unambiguously and separately indicate the number of filled Landau levels (LLs) in both $K$ and $K'$ valleys. This reveals the interaction-enhanced valley Zeeman energy, which is found to be highly tunable with hole density $p$. We exploit this tunability to align the LLs in $K$ and $K'$, and find that the 2D hole gas becomes unstable against small changes in LL filling and can spontaneously valley-polarize. These results cannot be understood within a single-particle picture, highlighting the importance of exchange interactions in determining the ground state of 2D carriers in monolayer semiconductors.

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