Giant gate-controlled room temperature odd-parity magnetoresistance in magnetized bilayer graphene

TL;DR

This study reports a giant, tunable odd-parity magnetoresistance at room temperature in a bilayer graphene heterostructure with Cr$_2$Te$_2$Ge$_6$, revealing intrinsic time-reversal symmetry breaking and Berry curvature effects.

Contribution

It demonstrates the discovery of giant room temperature odd-parity magnetoresistance in bilayer graphene heterostructures and explains its origin through Berry curvature coupling.

Findings

Significant antisymmetric longitudinal magnetoresistance observed.

OMR is tunable via electrostatic gating.

OMR diminishes with increased charge carrier density.

Abstract

Magnetotransport measurements are crucial for understanding the Fermi surface properties, magnetism, and topology in quantum materials. Here, we report the discovery of giant room temperature odd-parity magnetoresistance (OMR) in a bilayer graphene (BLG) heterostructure interfaced with Cr$_2$Te$_2$Ge$_6$ (CGT). Using magnetotransport measurements, we demonstrate that the BLG/CGT heterostructure exhibits a significant antisymmetric longitudinal magnetoresistance, indicative of intrinsic time-reversal symmetry (TRS) breaking in the system. We show that the OMR is tunable via electrostatic gating. Additionally, the OMR is pronounced near the band edges and diminishes with increasing charge carrier density in graphene. Our theoretical analysis reveals that this phenomenon arises from the coupling of the out-of-plane components of Berry curvature and orbital magnetic moment to the applied magnetic field in a TRS-broken system. Our findings establish OMR as a significant probe for TRS breaking in quantum materials in which the crystal symmetries preclude the appearance of anomalous Hall effect.