1. CNR‐SPIN C.so F.M. Perrone 24 16152 Genova Italy
2. Key Laboratory of Microelectronics Devices and Integration TechnologyInstitute of Microelectronics of Chinese Academy of Sciences 100029 Beijing China
3. State Key Laboratory of Crystal Materials and the Key Laboratory of Functional Crystal Materials and DeviceShandong University 250100 Jinan China
4. The School of MicroelectronicsUniversity of Science and Technology of China 230026 Hefei China