[1] Westfalische Wilhelms Univ Munster, Inst Solid State Theory, Wilhelm Klemm Str 10, D-48149 Munster, Germany
[2] Westfalische Wilhelms Univ Munster, Ctr Multiscale Theory & Computat, Wilhelm Klemm Str 10, D-48149 Munster, Germany
[3] Westfalische Wilhelms Univ Munster, Inst Phys, Wilhelm Klemm Str 10, D-48149 Munster, Germany
[4] Westfalische Wilhelms Univ Munster, Ctr Nanotechnol, Wilhelm Klemm Str 10, D-48149 Munster, Germany