Fractional quantum Hall phases in high-mobility n-type molybdenum disulfide transistors
Siwen Zhao, Jinqiang Huang, Valentin Crépel, Zhiren Xiong, Xingguang Wu, Tongyao Zhang, Hanwen Wang, Xiangyan Han, Zhengyu Li, Chuanying Xi, Senyang Pan, Zhaosheng Wang, Guangli Kuang, Jun Luo, Qinxin Shen, Jie Yang, Rui Zhou, Kenji Watanabe, Takashi Taniguchi, Benjamin Sacépé, Jing Zhang, Ning Wang, Jianming Lü, Nicolas Regnault, Zheng Han
Abstract
Abstract Transistors based on semiconducting transition metal dichalcogenides can, in theory, offer high carrier mobilities, strong spin–orbit coupling and inherently strong electronic interactions at the quantum ground states. This makes them well suited for use in nanoelectronics at low temperatures. However, creating robust ohmic contacts to transition metal dichalcogenide layers at cryogenic temperatures is difficult. As a result, it is not possible to reach the quantum limit at which the Fermi level is close to the band edge and thus probe electron correlations in the fractionally filled Landau-level regime. Here we show that ohmic contacts to n-type molybdenum disulfide can be created over a temperature range from millikelvins to 300 K using a window-contacted technique. We observe field-effect mobilities of over 100,000 cm 2 V −1 s −1 and quantum mobilities of over 3,000 cm 2 V −1 s −1 in the conduction band at low temperatures. We also report evidence for fractional quantum Hall states at filling fractions of 4/5 and 2/5 in the lowest Landau levels of bilayer molybdenum disulfide.