Work

Berezinskii-Kosterlitz-Thouless transition and anomalous metallic phase in a hybrid Josephson junction array

Year: 2024

Type: article

Abstract: We investigate the Berezinskii-Kosterlitz-Thouless (BKT) transition in a semiconductor-superconductor two-dimensional Josephson junction array. Tuned by an electrostatic top gate, the system exhibits separate superconducting (S), anomalous metal (M*), and insulating (I) phases, bordered by separatrices of the temperature-dependent sheet resistance ${R}_{s}$. We find that the gate-dependent BKT transition temperature falls to zero at the S-M* boundary, suggesting incomplete vortex-antivortex pairing in the M* phase. In the S phase, ${R}_{s}$ is roughly proportional to the perpendicular magnetic field at the BKT transition, as expected, while in the M* phase, ${R}_{s}$ deviates from its zero-field value as a power law in the field with exponent close to 1/2 at low temperature. An in-plane magnetic field eliminates the M* phase, leaving a small scaling exponent at the S-I boundary, which we interpret as a remnant of the incipient M* phase.

Source: Physical review. B./Physical review. B

DOI: 10.1103/physrevb.110.l180502

Authors: C. G. L. Bøttcher, F. Nichele, J. Shabani, C. J. Palmstrøm, C. M. Marcus

Institutions: University of Copenhagen, California NanoSystems Institute, University of California, Santa Barbara

Language: English

Topic: Physics of Superconductivity and Magnetism

Subfield: Condensed Matter Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Microsoft, Villum Fonden, National Research Foundation, Danmarks Grundforskningsfond

Awards: G2927648586, G6069308275