1. Chair of Solid-State and Quantum Chemistry, Institute of Inorganic Chemistry RWTH Aachen University 52056 Aachen Germany
2. 2nd Institute of Physics A RWTH Aachen University 52074 Aachen Germany
3. Hoffmann Institute of Advanced Materials Shenzhen Polytechnic 7098 Liuxian Blvd, Nanshan District Shenzhen 518055 China