Current-induced giant diamagnetism in the Mott insulator Ca2RuO4

TL;DR

This paper reports a novel giant diamagnetism induced by electric current in the Mott insulator Ca2RuO4, caused by emergent Dirac cones and monopole-like anomalies, representing a new non-equilibrium quantum phenomenon.

Contribution

It demonstrates a new type of switchable, giant diamagnetism in a Mott insulator driven by electric current, linked to many-body Dirac cones and topological anomalies.

Findings

Induces record-breaking diamagnetism with 1 A/cm2 current.

Identifies emergence of indirect Dirac cones in the spectrum.

Reveals monopole-like anomalies in susceptibility.

Abstract

Mott insulators have surprised us many times by hosting new and diverse quantum phenomena when the frozen electrons are perturbed by various stimuli. Superconductivity, metal-insulator transition, and colossal magnetoresistance induced by element substitution, pressure, and magnetic field are prominent examples. Here we report a novel phenomenon, namely giant diamagnetism, in the Mott insulator Ca2RuO4 induced by electric current. With application of 1 A/cm2 current, the strongest diamagnetism among all nonsuperconducting materials is induced as the system is tuned to a semimetallic state. The origin lies in the emergence of indirect Dirac cones in the many-body spectrum and associated monopole-like anomaly in the momentum dependent susceptibility. This record-breaking and switchable diamagnetism is a new class of non-equilibrium quantum phenomena on the verge of Mott insulating states.