Quantum Phase Transitions with Dissipation

Current experiments focus on the superconductor-insulator (SI) transition in 2-D films of amorphous MoGe. The transition, which is either field or disorder driven, is expected to obey certain scaling laws. Recent experiments show that these scaling laws may not in fact be obeyed at the lowest temperatures, due to a coupling of the SI system to dissipation. The data (above) shows the manifestation of this dissipative coupling as low temperature metallic behavior (or, saturation of resistance). Experiments are performed in a dilution refrigerator.