Affiliation: | 1. Department of Materials Science and Engineering , The Pennsylvania State University , University Park, Pennsylvania 16802 , USA;2. Department of Physics , University of Science and Technology Beijing , Beijing 100083 , China wjj8384@gmail.com;4. Department of Materials Science and Engineering , The Pennsylvania State University , University Park, Pennsylvania 16802 , USA;5. State Key Laboratory for Mechanical Structural Strength and Vibration , School of Aerospace, Xi’an Jiaotong University , 710049, China;6. Department of Physics , University of Science and Technology Beijing , Beijing 100083 , China |