Upper Critical Field in the Molecular Organic Superconductor (DMET)2I3

TL;DR

This study investigates the temperature dependence of the upper critical magnetic field in the quasi-one-dimensional organic superconductor (DMET)2I3, revealing conventional spin singlet pairing and a magnetic field-induced dimensional crossover.

Contribution

It provides the first detailed measurement of the upper critical field in (DMET)2I3 along different directions, showing saturation at low temperatures and no exceeding of the Pauli limit, contrasting with similar materials.

Findings

Upper critical field saturates at low temperature in all directions.

Superconductivity is consistent with conventional spin singlet pairing.

Evidence of a magnetic field-induced dimensional crossover in the normal state.

Abstract

We report the temperature dependence of the upper critical magnetic field in the quasi-onedimensional molecular organic superconductor (DMET)2I3, for magnetic field applied along the intrachain, interchain, and interplane directions. The upper critical field tends to saturation at low temperature for field in all directions and does not exceed the Pauli paramagnetic limit. Superconductivity in (DMET)2I3 thus appears to be conventional spin singlet, in contrast to the status of the isostructural Bechgaard salts. We also discuss a magnetic field-induced dimensional crossover effect in the normal metallic state which had previously appeared to be associated with superconductivity.