1. Department of Physics Korea Advanced Institute of Science and Technology (KAIST) Daejeon 34141 South Korea
2. Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics, Beijing Institute of Technology Beijing 100081 China
3. CINTRA CNRS/NTU/THALES Research Techno Plaza Nanyang Technological University Singapore 637371 Singapore
4. School of Materials Science and Engineering Nanyang Technological University Singapore Singapore
5. International Center for Materials Nanoarchitectonics National Institute for Materials Science 1‐1 Namiki Tsukuba 3030044 Japan