1. CAS Center for Excellence in NanoscienceBeijing Key Laboratory of Micro‐Nano Energy and SensorBeijing Institute of Nanoenergy and NanosystemsChinese Academy of Sciences Beijing 100083 P. R. China
2. School of Nanoscience and TechnologyUniversity of Chinese Academy of Sciences Beijing 100048 P. R. China
3. MOE Key Laboratory of Fundamental Physical Quantities Measurement and HubeiKey Laboratory of Gravitation and Quantum PhysicsPGMF and School of PhysicsHuazhong University of Science and Technology Wuhan 430074 P. R. China
4. New Materials InstituteDepartment of MechanicalMaterials and Manufacturing EngineeringUniversity of Nottingham Ningbo China Ningbo 315100 P. R. China
5. Center on Nanoenergy ResearchSchool of Physical Science and TechnologyGuangxi University Nanning 530004 P. R. China
6. School of Materials Science and EngineeringGeorgia Institute of Technology Atlanta GA 30332 USA