1. Department of Electrical and Biological Physics Kwangwoon University Wolgye‐Dong Seoul 01897 South Korea
2. Nanotechnology Research Laboratory, Faculty of Engineering Sciences GIK Institute of Engineering Sciences and Technology Topi Khyber Pakhtunkhwa 23640 Pakistan
3. School of Physics Peking University Beijing 100871 China
4. IBS Center for Integrated Nanostructure Physics Sungkyunkwan University Suwon 16419 South Korea
5. School of Physics and School of Microelectronics Dalian University of Technology Dalian 116000 China