In superconductors the zero-resistance current-flow is protected from dissipation at finite temperatures (T) by virtue of the short-circuit condition maintained by the electrons that remain in the condensed state. The recently suggested finite-T insulator and the "superinsulating" phase are different because any residual mechanism of conduction will eventually become dominant as the finite-T insulator sets-in. If the residual conduction is small it may be possible to observe the transition to these intriguing states. We show that the conductivity of the high magnetic-field insulator terminating superconductivity in amorphous indium-oxide exhibits an abrupt drop, and seem to approach a zero conductance at T<0.04 K. We discuss our results in the light of theories that lead to a finite-T insulator.
@article{arxiv.1406.7510,
title = {Evidence for a Finite Temperature Insulator},
author = {M. Ovadia and D. Kalok and I. Tamir and S. Mitra and B. Sacepe and D. Shahar},
journal= {arXiv preprint arXiv:1406.7510},
year = {2016}
}