Enhancement of Superconductivity in WP via Oxide-Assisted Chemical Vapor Transport

TL;DR

This study demonstrates that oxide-assisted chemical vapor transport significantly enhances the superconducting transition temperature of tungsten monophosphide (WP) from below 0.8 K to above 1 K, with improved crystal quality.

Contribution

The paper introduces a new CVT synthesis method using WO3, P, and I2 that improves WP crystal quality and raises its superconducting transition temperature.

Findings

Superconductivity in WP is enhanced above 1 K using CVT.

Samples show decreased low-temperature scattering and more 3D morphology.

Variation in Tc suggests influence from competing orders or non s-wave pairing.

Abstract

Tungsten monophosphide (WP) has been reported to superconduct below 0.8 K, and theoretical work has predicted an unconventional Cooper pairing mechanism. Here we present data for WP single crystals grown by means of chemical vapor transport (CVT) of WO3, P, and I2. In comparison to synthesis using WP powder as a starting material, this technique results in samples with substantially decreased low-temperature scattering and favors a more three dimensional morphology. We also find that the resistive superconducting transitions in these samples begin above 1 K. Variation in Tc is often found in strongly correlated superconductors, and its presence in WP could be the result of influence from a competing order and/or a non s-wave gap.