1. L-NESS and Department
of Materials Science, Università di Milano-Bicocca, Via
R. Cozzi 55, I-20126, Milano, Italy
2. Laboratory for Solid State
Physics, ETH Zürich, Otto-Stern-Weg 1, CH-8093, Zürich, Switzerland
3. L-NESS and Department of Physics, Politecnico di Milano, Via F. Anzani 42, I-22100, Como, Italy
4. Institut für
Wissenschaftliches Rechnen, Technische Universität Dresden, Zellescher Weg
12-14, D-01069, Dresden, Germany
5. IHP, Im Technologiepark 25, D-15236, Frankfurt (Oder), Germany
6. Department
of Science, Università Roma Tre, Viale Marconi 446, I-00146, Roma, Italy