Nonlinear electric transport in graphene with magnetic disorder

TL;DR

This paper explores how magnetic impurities affect nonlinear electric transport in graphene under strong electric fields, revealing phase-dependent behaviors including localization and multifractal states.

Contribution

It provides a detailed analysis of magnetic disorder effects on graphene's nonlinear transport, highlighting phase transitions and multifractal electronic states.

Findings

Paramagnetic phase maintains transport similar to clean graphene.

Antiferromagnetic phase exhibits transition from superdiffusive to subdiffusive behavior.

Conductivity reduces to half the minimum in the localized state.

Abstract

The influence of magnetic impurities on the transport properties of graphene is investigated in the regime of strong applied electric fields. As a result of electron-hole pair creation, the response becomes nonlinear and dependent on the magnetic polarization. In the paramagnetic phase, time reversal symmetry is statistically preserved, and transport properties are similar to the clean case. At variance, in the antiferromagnetic phase, the system undergoes a transition between a superdiffusive to a subdiffusive spreading of a wave packet, signaling the development of localized states. This critical regime is characterized by the appearance of electronic states with a multifractal geometry near the gap. The local density of states concentrates in large patches having a definite charge-spin correlation. In this state, the conductivity tends to half the minimum conductivity of clean graphene.