1. School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 P. R. China
2. Institute for Integrative Nanosciences Leibniz IFW Dresden 01069 Dresden Germany
3. Institute of Ion Beam Physics and Materials Research Helmholtz‐Zentrum Dresden‐Rossendorf 01328 Dresden Germany
4. Institute for Solid State Research Leibniz IFW Dresden 01069 Dresden Germany
5. Faculty of Physics TU Dresden 01062 Dresden Germany
6. Material Systems for Nanoelectronics TU Chemnitz 09107 Chemnitz Germany
7. Research Center for Materials Architectures and Integration of Nanomembranes (MAIN) TU Chemnitz 09126 Chemnitz Germany