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arXiv 1601.01418cond-mat.mtrl-sci
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MoS $_2$，MoSe $_2$，WS $_2$和WSe $_2$的大量狄拉克费米子模型参数的实验测定

Experimental determination of the massive Dirac fermion model parameters for MoS$_2$, MoSe$_2$, WS$_2$, and WSe$_2$

Beom Seo Kim, Jun-Won Rhim, Beomyoung Kim, Changyoung Kim, Seung Ryong Park

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11 pages, 6 figures, 1 table
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摘要：

单层MX $_2$（M = Mo，W; X = S，Se）由于其在光电子学、自旋电子学和谷电子学等方面的潜在应用前景，近年来引起了人们的广泛关注。其奇异的光学和电子性质包括直接带隙、圆偏振相关的光学跃迁以及在$K$和$-K$点处的价带（VB）自旋带分裂。这些性质可以在一个极小模型中描述，称为大质量狄拉克费米子模型，其参数需要通过实验确定。我们建议，可以从角分辨光电子能谱（ARPES）数据从散装2H-MX $_2$，而不是单层MX $_2$。通过紧束缚计算，我们显示了如何在高对称点的电子结构演变的系统从单层到三维块体2H-MX $_2$。我们发现消失的$k_z$色散和几乎没有变化的直接带隙在$K$和$-K$点，在强烈的$k_z$色散在$Γ$点形成鲜明对比。这些事实使我们能够提取的间隙和自旋带分裂的$K$点，以及跳跃能量从散装ARPES数据。我们在不同光子能量和钾蒸发下对MoS $_2$、MoSe $_2$、WS $_2$和WSe $_2$单晶进行了ARPES实验。根据这些数据，我们确定了单层MoS $_2$、MoSe $_2$、WS $_2$和WSe $_2$的大质量狄拉克费米子模型的参数。

英文摘要：

Monolayer MX$_2$ (M = Mo, W; X = S, Se) has drawn much attention recently for its possible application possibilities for optoelectronics, spintronics, and valleytronics. Its exotic optical and electronic properties include a direct band gap, circular polarization dependent optical transitions, and valence band (VB) spin band splitting at the $K$ and $-K$ points. These properties can be described within a minimal model, called the massive Dirac fermion model for which the parameters need to be experimentally determined. We propose that the parameters can be obtained from angle resolved photoemission (ARPES) data from bulk 2H-MX$_2$, instead of monolayer MX$_2$. Through tight binding calculations, we show how the electronic structure at high symmetry points evolves as the system changes from the monolayer to the three dimensional bulk 2H-MX$_2$ . We find vanishing $k_z$ dispersion and almost no change in the direct band gap at the $K$ and $-K$ points, in sharp contrast to the strong $k_z$ dispersion at the $Γ$ point. These facts allow us to extract the gap and spin band splitting at the $K$ point as well as the hopping energy from bulk ARPES data. We performed ARPES experiments on single crystals of MoS$_2$, MoSe$_2$, WS$_2$, and WSe$_2$ at various photon energies and also with potassium evaporation. From the data, we determined the parameters for the massive Dirac fermion model for monolayer MoS$_2$, MoSe$_2$, WS$_2$, and WSe$_2$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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