1. College of Materials Science and Engineering; Guilin Univeristy of Techonology; Guilin China
2. Electronic Materials Research Laboratory-Key Laboratory of the Ministry of Education and International Center for Dielectric Research; Xi'an Jiaotong University; Xi'an China
3. School of Physical Science & Technology and Guangxi Key Laboratory for Relativistic Astrophysics; Guangxi University; Nanning China
4. School of Microelectronics and State Key Laboratory for Mechanical Behaviour of Materials; Xi'an Jiaotong University; Xi'an China