Hopping transport in granular superconductors

A. V. Lopatin; V. M. Vinokur

doi:10.1103/PhysRevB.75.092201

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Hopping transport in granular superconductors

A. V. Lopatin, V. M. Vinokur

DOI 10.1103/PhysRevB.75.092201 · Physical Review B

T1

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Abstract

We investigate hopping transport in granular superconductors in the weak-coupling insulating regime and find that it is governed by the interplay between the granule charging energy Ec and the single granule superconducting gap Δ. At Ec>Δ, the transport is mediated by single electron hopping, while at Ec<Δ, the transport is dominated by hopping of Cooper pairs. We show that in the former case and at low temperatures, T⪡Δ<Ec, superconducting pairing suppresses inelastic cotunneling processes, giving rise to giant negative magnetoresistance. We find the range of intermediate temperatures where transport is dominated by inelastic cotunneling but having an activation temperature behavior; this regime is specific to granular superconductors. We investigate different conductivity regimes and construct a transport phase diagram.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
La3Ni2O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown