* Corresponding authors

^a Institute for Advanced Interdisciplinary Research, University of Jinan, Jinan, Shandong, China
E-mail: ifc_wangaz@ujn.edu.cn

^b Department of Electrical and Computer Engineering and Department of Physics, National University of Singapore, Singapore, Singapore

^c Department of Mechanical Engineering, Engineering Science Programme, Faculty of Engineering, National University of Singapore, Singapore, Singapore

^d School of Physics and State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
E-mail: zmw@sdu.edu.cn

^e Department of Physics & Centre for Advanced Two-dimensional Materials, National University of Singapore, Singapore, Singapore
E-mail: phyfyp@nus.edu.sg

^f State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
E-mail: hongliu@sdu.edu.cn