Applied Materials Physics, Department of Materials Sci. & Eng., The Royal Inst of Technology, Brinellvagen 23, Stockholm, 100 44 Sweden ; Condensed Matter Theory Group, Department of Physics, AlbaNova University Center, The Royal Inst of Technology, Roslagstullbacken 13, Stockholm, 10691 Sweden
Condensed Matter Theory Group, Department of Physics, Uppsala University, BOX 530, Uppsala, 75121 Sweden
Condensed Matter Theory Group, Department of Physics, AlbaNova University Center, The Royal Inst of Technology, Roslagstullbacken 13, Stockholm, 10691 Sweden
Condensed Matter Theory Group, Department of Physics, Uppsala University, BOX 530, Uppsala, 75121 Sweden
Applied Materials Physics, Department of Materials Sci. & Eng., The Royal Inst of Technology, Brinellvagen 23, Stockholm, 100 44 Sweden ; Condensed Matter Theory Group, Department of Physics, Uppsala University, BOX 530, Uppsala, 75121 Sweden
Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, Los Alamos, NM 87545 United States
Physics Division, Los Alamos National Laboratory, Los Alamos, NM, Los Alamos, NM 87545 United States