Quantum Superconductor-Metal Transitions in the Presence of Quenched Disorder
InOx films that are less disordered than those exhibiting direct quantum superconductor-insulator transitions feature quantum superconductor-metal transitions tuned by magnetic field. Resistance data across this superconductor-metal transition obey activated scaling, with critical exponents suggesting that the transition is governed by an infinite-randomness critical point in the universality class of the random transverse-field Ising model in two dimensions. The transition is accompanied by quantum Griffiths effects. This unusual behavior is expected for systems with quenched disorder in the presence of ohmic dissipation. Disorder leads to the formation of large rare regions which are locally ordered superconducting puddles dispersed in a metallic matrix. Their dissipative dynamics causes the activated scaling, as predicted by a renormalization group theory.
N. A. Lewellyn et al., "Quantum Superconductor-Metal Transitions in the Presence of Quenched Disorder," Journal of Superconductivity and Novel Magnetism, vol. 33, no. 1, pp. 183-190, Springer, Jan 2020.
The definitive version is available at https://doi.org/10.1007/s10948-019-05250-1
Keywords and Phrases
Quantum Griffiths effects; Quenched disorder; Superconductor-metal transitions
International Standard Serial Number (ISSN)
Article - Journal
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01 Jan 2020