1Department of Physics, College of Sciences, Hue University, 77 Nguyen Hue St., Hue City, Vietnam
2Department of Physics, Duy Tan University, 182 Nguyen Van Linh, Thanh Khe District, Da Nang, Vietnam
3Institute of Materials Science, Vietnam Academy of Science and Technology, Cau Giay District, Hanoi, Vietnam
Read More: http://www.worldscientific.com/doi/abs/10.1142/S0217979215502318