Valence Band Splitting on Multilayer MoS2: Mixing of Spin–Orbit Coupling and Interlayer Coupling

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• 作者：Xiaofeng Fan ; David J. Singh ; Weitao Zheng
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：June 16, 2016
• 年：2016
• 卷：7
• 期：12
• 页码：2175-2181
• 全文大小：425K
• 年卷期：0
• ISSN：1948-7185

文摘

Understanding the origin of valence band splitting is important because it governs the unique spin and valley physics in few-layer MoS₂. We explore the effects of spin–orbit coupling and interlayer coupling on few-layer MoS₂ using first-principles methods. We find spin–orbit coupling has a major contribution to the valence band splitting at K in multilayer MoS₂. In double-layer MoS₂, the interlayer coupling leads to the widening of the gap between the already spin–orbit split states. This is also the case for the bands of the K-point in bulk MoS₂. In triple-layer MoS₂, the strength of interlayer coupling of the spin-up channel becomes different from that of spin-down at K. This combined with spin–orbit coupling results in the band splitting in two main valence bands at K. With the increase of pressure, this phenomenon becomes more obvious with a decrease of main energy gap in the splitting valence bands at the K valley.