Anisotropy of zero-resistance states in InN films under an in-plane magnetic filed

TL;DR

This study investigates the anisotropic behavior of zero-resistance states in InN films at low temperatures, revealing significant directional dependence of critical current under in-plane magnetic fields, linked to vortex dynamics.

Contribution

It provides the first detailed analysis of anisotropic zero-resistance states in InN films, demonstrating vortex flow as a key factor in their superconducting phenomenology.

Findings

Zero-resistance state observed at 0.3 K with a critical current of ~1 mA.

Critical current anisotropy ratio up to 2.5 under in-plane magnetic fields.

Vortex flow explains the anisotropic superconducting behavior.

Abstract

We report low temperature current-voltage measurements on n-type InN films grown by molecular beam epitaxy. The zero-resistance state with a large critical current around 1 mA has been observed at 0.3 K. Under in-plane field configuration, the zero-resistance state shows a large anisotropy in critical current for B parallel and perpendicular to applied current. The ratio of critical current between B parallel and perpendicular to the applied current can be up to 2.5, when B = 0.15T. The anisotropy is explained by the vortex flow in the context of type II superconductivity. We have thus established an important aspect of the phenomenology of superconductivity in an otherwise typical narrow gap semiconductor.