1. Research Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044, Japan
2. Integrated Photonics Technologies Unit, Microsystems Division, Silicon Austria Laboratories (SAL), Europastraße 12, 9524 Villach, Austria
3. Research Network and Facility Services Division, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan
4. Center for Basic Research on Materials, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan
5. Institute of Physics, P. O. Sainik School, Bhubaneswar 751005, India
6. Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
7. Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India
8. Department of Condensed Matter Physics, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan