Emergent scalar-chirality \& colossal transverse-magnetoresponse in strongly correlated nodal-line half-metal

TL;DR

This paper explores how strong correlations and temperature influence nodal-line semimetals, revealing emergent scalar chirality and colossal transverse magnetoresponse in a specific double-perovskite material.

Contribution

It provides first-principles and Monte Carlo simulations showing the emergence of scalar chirality and giant magnetoresponse in a strongly correlated nodal-line half-metal.

Findings

SOC gaps out nodal points and causes band inversion.

Emergent Co-spin scalar chirality at finite temperature.

Colossal positive transverse magnetoresponse predicted.

Abstract

Understanding the interplay of strong correlation and temperature in nodal-line semimetals can offer novel ways to control spin currents. Here we consider the 3d-5d double-perovskite Ba$_{2}$CoWO$_{6}$, which features mirror-symmetry-protected nodal-lines, strong Co-site interactions, and spin-orbit coupling (SOC) at W sites. Our first principles and exact diagonalization results reveal a half-metallic ground state with high-spin Co and topologically non-trivial bands. We demonstrate that SOC gaps out nodal points, causes band-inversion and generates anomalous Hall response. A semi-classical Monte Carlo finite-temperature simulation of five-orbital Hubbard model uncovers an emergent Co-spin scalar chirality and colossal positive transverse-magnetoresponse. We predict the temperature and magnetic field scales for the tunability of scalar-chirality and magnetoresponse.