Large Diamagnetism and Electromagnetic Duality in Two-dimensional Dirac Electron System

TL;DR

This study reveals large orbital diamagnetism and electromagnetic duality in a 2D Dirac organic conductor, showing relativistic effects influence solid-state electromagnetic responses over a wide temperature range.

Contribution

It demonstrates the revival of relativistic electromagnetic duality in a solid-state system, evidenced by large diamagnetism and conductivity scaling in a 2D Dirac material.

Findings

Large orbital diamagnetism along interplane direction

Conductance of order e^2/h nearly temperature-independent

Diamagnetism scales with electrical conductivity

Abstract

A Dirac electron system in solids mimics a relativistic quantum physics that is compatible with Maxwell's equations, by which we anticipate unified electromagnetic responses. We find a large orbital diamagnetism only along the interplane direction and the nearly temperature-independent conductance of the order of e2/h for the new 2D Dirac organic conductor, a-(BETS)2I3. Distinct from conventional electrons in solids whose nonrelativistic effects bifurcate electric and magnetic responses, the observed orbital diamagnetism scales the electrical conductivity for a wide temperature range. This demonstrates that an electromagnetic duality that is valid only within the relativistic framework is revived in solids.