Affiliation: | (1) Department of Physics, Changchun University, Changchun, 130022, P.R. China;(2) Key Laboratory of Low Dimensional Materials and Application Technology (Ministry of Education), Xiangtan University, Xiangtan, Hunan, 411105, China;(3) Faculty of Materials and Optoelectronic Physics, Xiangtan University, Xiangtan, Hunan, 411105, China;(4) Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada, T6G 2G8; |