1. Department of Physics Indian Institute of Science Bangalore 560012 India
2. Research Center for Functional Materials National Institute for Materials Science 1‐1 Namiki Tsukuba 305‐0044 Japan
3. International Center for Materials Nanoarchitectonics National Institute for Materials Science 1‐1 Namiki Tsukuba 305‐0044 Japan
4. Center for Nano Science and Engineering Indian Institute of Science Bangalore 560012 India