Department of Physics, Florida Atlantic University, 777 Glades Road, Boca Raton 33431-0991, USA. yyu@fau.edu|Department of Physics, Florida Atlantic University, 777 Glades Road, Boca Raton 33431-0991, USA. yyu@fau.edu|Department of Physics, Florida Atlantic University, 777 Glades Road, Boca Raton 33431-0991, USA. yyu@fau.edu