[1] Univ Regensburg, Inst Inorgan Chem, Univ Str 31, D-93053 Regensburg, Germany
[2] Univ Augsburg, Inst Phys, Chair Solid State & Mat Sci, Univ Str 1, D-86159 Augsburg, Germany
[3] Friedrich Alexander Univ Erlangen Nurnberg, Erlangen Ctr Interface Res & Catalysis, Egerlandstr 3, D-91058 Erlangen, Germany