1. Key Laboratory for Renewable Energy, Beijing Key Laboratory for New
Energy Materials and Devices, National Laboratory for Condensed Matter
Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
2. School
of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
3. Department
of Physics and Astronomy, California State University Northridge, Northridge, California 91330-8268, United States
4. Department of Physics, Laboratory of Computational
Materials Physics, Jiangxi Normal University, Nanchang, Jiangxi 330022, China