Emergent anisotropic three-phase order in critically doped superconducting diamond films

TL;DR

This study uncovers intrinsic electronic granularity and emergent anisotropic three-phase order in critically doped superconducting diamond films, revealing complex magnetic and transport phenomena relevant to quantum technology applications.

Contribution

It demonstrates the presence of intrinsic electronic granularity and anisotropic three-phase order in heavily boron-doped diamond, advancing understanding of its superconducting mechanism.

Findings

Identified signatures of intrinsic electronic granularity in HBDD films.

Discovered a three-phase anisotropy in magnetoresistance and a Hall anomaly.

Revealed magnetically tunable intrinsic order in isotropic diamond crystals.

Abstract

Two decades since its discovery, superconducting heavily boron-doped diamond (HBDD) still presents unresolved fundamental questions whose resolution is relevant to the development of this material for quantum technologies. We use electrical magnetotransport measurements of critically-doped homoepitaxial single crystal HBDD films to reveal signatures of intrinsic (electronic) granular superconductivity. By studying the dependence of electrical resistivity on temperature and magnetic field vector, we infer that this granularity arises from electron correlations. This is revealed by a striking three-phase anisotropy in the magnetoresistance, accompanied by a spontaneous transverse voltage (Hall anomaly). Our findings indicate an emergent magnetically tunable intrinsic order in an otherwise isotropic three dimensional single crystal HBDD film, offering new insights into the mechanism of superconductivity in this quantum material.