1. Institute of Applied Physics, Technische Universität (TU) Dresden, Nöthnitzer Strasse 61, 01187 Dresden, Germany
2. Institute of Physics of the Czech Academy of Sciences, 18221 Prague, Czech Republic
3. ct.qmat: Dresden-Würzburg Cluster of Excellence─EXC 2147, Technische Universität (TU) Dresden, 01062 Dresden, Germany