Even–odd layer-dependent magnetotransport of high-mobility Q-valley electrons in transition metal disulfides

• Published in: Nature communications 2016-09, Vol.7 (1), p.12955-12955, Article 12955
• Main Authors: Wu, Zefei, Xu, Shuigang, Lu, Huanhuan, Khamoshi, Armin, Liu, Gui-Bin, Han, Tianyi, Wu, Yingying, Lin, Jiangxiazi, Long, Gen, He, Yuheng, Cai, Yuan, Yao, Yugui, Zhang, Fan, Wang, Ning
• Format: Article
• Language: English
• Subjects: 142/126; 639/766/119/1000/1018; 639/766/119/2794; 639/766/119/995; 639/925/927/1007; Asymmetry; Electrons; Etching; Humanities and Social Sciences; multidisciplinary; Physics; Science; Science (multidisciplinary); Symmetry; Temperature
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms12955

In few-layer transition metal dichalcogenides (TMDCs), the conduction bands along the ΓK directions shift downward energetically in the presence of interlayer interactions, forming six Q valleys related by threefold rotational symmetry and time reversal symmetry. In even layers, the extra inversion symmetry requires all states to be Kramers degenerate; whereas in odd layers, the intrinsic inversion asymmetry dictates the Q valleys to be spin-valley coupled. Here we report the transport characterization of prominent Shubnikov-de Hass (SdH) oscillations and the observation of the onset of quantum Hall plateaus for the Q-valley electrons in few-layer TMDCs. Universally in the SdH oscillations, we observe a valley Zeeman effect in all odd-layer TMDC devices and a spin Zeeman effect in all even-layer TMDC devices, which provide a crucial information for understanding the unique properties of multi-valley band structures of few-layer TMDCs. Few-layer transition metal dichalcogenides exhibit strong spin-valley entanglement and unconventional quantum Hall states, however their study has been limited by electron mobility. Here, the authors explore how quantum transport varies between even- and odd-layered systems of high mobility.