title: Magnetotransport Properties in High-Quality Ultrathin Two-Dimensional Superconducting Mo2C Crystals.
abstract: Ultrathin transition metal carbides are a class of developing two-dimensional (2D) materials with superconductivity and show great potentials for electrical energy storage and other applications. Here, we report low-temperature magnetotransport measurements on high-quality ultrathin 2D superconducting α-Mo2C crystals synthesized by a chemical vapor deposition method. The magnetoresistance curves exhibit reproducible oscillations at low magnetic fields for temperature far below the superconducting transition temperature of the crystals. We interpret the oscillatory magnetoresistance as a consequence of screening currents circling around the boundary of triangle-shaped terraces found on the surface of ultrathin Mo2C crystals. As the sample thickness decreases, the Mo2C crystals exhibit negative magnetoresistance deep in the superconducting transition regime, which reveals strong phase fluctuations of the superconducting order parameters associated with the superconductor-insulator transition. Our results demonstrate that the ultrathin superconducting Mo2C crystals provide an interesting system for studying rich transport phenomena in a 2D crystalline superconductor with enhanced quantum fluctuations.
authors.affiliation: Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University , Beijing 100871, China.
authors.forename: Libin
authors.initials: L
authors.lastname: Wang
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Xu
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China.
authors.forename: Zhibo
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China.
authors.forename: Long
authors.initials: L
authors.lastname: Chen
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China.
authors.forename: Xiuliang
authors.initials: X
authors.lastname: Ma
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China.
authors.forename: Hui-Ming
authors.initials: HM
authors.lastname: Cheng
authors.affiliation: Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences , Shenyang 110016, China.
authors.forename: Wencai
authors.initials: W
authors.lastname: Ren
authors.affiliation: Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University , Beijing 100871, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Kang
keywords: magnetotransport properties; transition metal carbides; two-dimensional superconductivity