1. Center for Condensed Matter Sciences, National Taiwan University , Taipei, Taiwan, ROC
2. Department of Chemical Engineering and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University , Hsinchu, Taiwan, ROC
3. Department of Applied Chemistry, National Chiao Tung University , Hsinchu, Taiwan, ROC
4. Institute of Atomic and Molecular Sciences, Academia Sinica , Taipei, Taiwan, ROC