Affiliation: | 1. Key Laboratory of Materials Physics Anhui Key Laboratory of Nanomaterials and Nanostructures Institute of Solid State Physics, Chinese Academy of Sciences P. O. Box 1129, Hefei 230031 (PR China);2. Key Laboratory of Ion Beam Bioengineering Institute of Plasma Physics, Chinese Academy of Sciences Hefei 230031 (P. R. China) |