Affiliation: | 1. Key Laboratory of Materials Physics, and Anhui Key Laboratory of Nanomaterials and Nanostructures, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031 (P.?R. China);2. University of Science and Technology of China, Hefei 230026 (P.?R. China);3. Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (P.?R. China) |