Thermal activation of the vortex Mott insulator to metal transition

The magnetoresistance of a square array of superconducting islands placed on a normal metal is investigated. This system undergoes magnetic field and current induced phase transitions at rational values of the normalized magnetic field. Scaling analysis is done at integers fc = 1 and fc = 2. This was done previously in [1], where it is argued that the scaling behaviour is similar to that of an electronic Mott insulator, and it is argued that indeed the vortices induced by the magnetic field play the role of the electrons in an electronic Mott insulator. Here, the scaling exponents found in [1] are reproduced, and furthermore the scaling is done at fc = 3/2, which has the same scaling behaviour as the fc = 1/2 transition. Furthermore, by analysing the temperature dependence at the Vortex Mott transitions, it is concluded that the vortices are thermally activated, ruling out the possibility that this Vortex Mott transition is governed by quantum tunneling. Using this mapping from vortices to charges, vortex systems can be used as a tunable laboratory for realizing and exploring quantum many- body systems and their dynamics