1. School of Physics; University of Electronic Science and Technology of China, Chengdu; Sichuan 611731 PR China
2. Department of Electrical Engineering; Sukkur IBA University; Sukkur 65200 Pakistan
3. School of Resources and Environment; University of Electronic Science and Technology; Chengdu 611731 P.R. China
4. Texas Materials Institute, ETC 9.102; The University of Texas at Austin; Austin TX 78712 USA
5. Sichuan Alpha Scenery & Green Energy Co. Ltd.; PR China
6. Shenzen Li−S Technology Co.; Ltd. Shenzhen PR China