Magnetically Induced Metallic Phase in Superconducting Tantalum Films

TL;DR

This study reveals a previously unobserved metallic phase in disordered superconducting tantalum films under magnetic fields, challenging traditional views of superconducting-insulating transitions and showing similarities to other low-dimensional electron systems.

Contribution

It reports the discovery of a magnetically induced metallic phase in superconducting tantalum films, a phenomenon not previously documented in such materials.

Findings

Identification of three distinct transport regimes: superconducting, metallic, and insulating.

The metallic phase exhibits transport properties similar to MoGe films and 2D electron systems.

The metallic phase appears in the zero-temperature limit under magnetic fields.

Abstract

We have studied the electronic transport properties of homogeneously disordered superconducting tantalum thin films in magnetic fields. The films exhibit three distinct transport regimes in the zero temperature limit which we identify as superconducting, metallic, and insulating phases. The metallic phase is unexpected. The transport characteristics of this metallic phase are found to be similar to those of MoGe films and high mobility dilute two-dimensional electrons or holes confined in semiconductor interface or transistor geometry.