基金Project supported by Key Project of National Natural Science Foundation of China(50531060) National Science Found for Distinguished Young Scholars of China(10525211)+2 种基金 National Natural Science Foundation of China(10572124 10472099) Key Project of Scientific and Technological Department of Hunan Province (05FJ2005), and the Open Project Program of Low Dimensional Materials & Application Technology (Xiangtan University), Ministry of Education, China (KF0602).