Possible Current-Induced Phenomena and Domain Control in an Organic Dirac Fermion System with Weak Charge Ordering

TL;DR

This paper demonstrates that in an organic Dirac fermion system, unbalanced charge densities induce observable nonlinear Hall effects and orbital magnetization at zero magnetic field, with potential for domain control via current-induced magnetization.

Contribution

It introduces a novel method to selectively form single-domain states in an organic Dirac system using current-induced magnetization, enabling control over charge order domains.

Findings

Nonlinear anomalous Hall effect observed at zero magnetic field.

Current-induced orbital magnetization appears in the weak charge ordering state.

Proposed experimental method for domain control using current-induced magnetization.

Abstract

We show that when the electron and hole densities are unbalanced, observable nonlinear anomalous Hall effect and current-induced orbital magnetization appear at zero magnetic field in the weak charge ordering (CO) state of an organic two-dimensional Dirac fermion system, a-(BEDT-TTF)2I3. These current-induced phenomena are caused by a finite Berry curvature dipole resulting from inversion symmetry breaking and Dirac cone tilting. In the actual system, however, these effects are canceled out between different types of inversion asymmetric CO domains. To avoid the cancellation, we propose a new experimental method to realize the selective formation of a single type of domain using the current-induced magnetization.