Evolution of the Valley Position in Bulk Transition-Metal Chalcogenides and Their Monolayer Limit

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• 作者：Hongtao Yuan ; Zhongkai Liu ; Gang Xu ; Bo Zhou ; Sanfeng Wu ; Dumitru Dumcenco ; Kai Yan ; Yi Zhang ; Sung-Kwan Mo ; Pavel Dudin ; Victor Kandyba ; Mikhail Yablonskikh ; Alexei Barinov ; Zhixun Shen ; Shoucheng Zhang ; Yingsheng Huang ; Xiaodong Xu ; Zahid Hussain ; Harold Y. Hwang ; Yi Cui ; Yulin Chen
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：August 10, 2016
• 年：2016
• 卷：16
• 期：8
• 页码：4738-4745
• 全文大小：628K
• 年卷期：0
• ISSN：1530-6992

文摘

Layered transition metal chalcogenides with large spin orbit coupling have recently sparked much interest due to their potential applications for electronic, optoelectronic, spintronics, and valleytronics. However, most current understanding of the electronic structure near band valleys in momentum space is based on either theoretical investigations or optical measurements, leaving the detailed band structure elusive. For example, the exact position of the conduction band valley of bulk MoS₂ remains controversial. Here, using angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES), we systematically imaged the conduction/valence band structure evolution across representative chalcogenides MoS₂, WS₂, and WSe₂, as well as the thickness dependent electronic structure from bulk to the monolayer limit. These results establish a solid basis to understand the underlying valley physics of these materials, and also provide a link between chalcogenide electronic band structure and their physical properties for potential valleytronics applications.