Robert I. Shekhter a, ⁎
, Leonid Y. Gorelik b, Gustav Sonne a, Mats Jonson a, c, d
a Department of Physics, University of Gothenburg, SE-412 96 Göteborg, Sweden
b Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
c SUPA, Department of Physics, Heriot–Watt University, Edinburgh EH14 4AS, Scotland, UK
d Department of Physics, Division of Quantum Phases and Devices, Konkuk University, Seoul 143-107, Republic of Korea