The Berezinskii-Kosterlitz-Thouless Transition and Anomalous Metallic Phase in a Hybrid Josephson Junction Array

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 of 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 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 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.

7 pages, 4 figures

References in corpus (5)

• Quantum breakdown of superconductivity in low-dimensional materials
• Hard superconducting gap in germanium
• Stabilizing Superconductivity in Nanowires by Coupling to Dissipative Environments
• Anomalous metals: from "failed superconductor" to "failed insulator"
• Magnetic-Field-Induced Superconductivity in Ultrathin Pb Films with Magnetic Impurities

Cited by in corpus (4)

• Voltage-tuned anomalous-metal to metal transition in hybrid Josephson junction arrays
• Berezinskii-Kosterlitz-Thouless Renormalization Group Flow at a Quantum Phase Transition
• Engineering a Josephson junction chain for the simulation of the clock model
• Microwave radiometry of a quantum-critical, hybrid Josephson array