1. Department of Physics and Texas Center for Superconductivity (TcSUH), University of Houston, Houston, TX 77204, USA
2. Materials Science and Engineering Program, University of Houston, Houston, TX 77204, USA
3. College of Physical Science and Technology, Central China Normal University, Wuhan 430079, China
4. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
5. Department of Chemistry, University of Houston, Houston, Texas 77204, USA