Detecting Lifshitz Transitions Using Nonlinear Conductivity in Bilayer Graphene

TL;DR

This study demonstrates that nonlinear electrical response in bilayer graphene can detect Lifshitz transitions, with sign changes near these transitions and high conductivity levels, offering a new method to explore electronic band structures.

Contribution

We show that NLER in bilayer graphene reveals Lifshitz transitions through sign changes and high conductivity, providing a novel probe for electronic band structure analysis.

Findings

NLER sign changes near Lifshitz transitions at elevated temperatures.

NLER exceeds 30 μmV$^{-1}$Ω$^{-1}$ at 3K, surpassing previous results.

NLER is modulated by doping and interlayer potential, influenced by scattering and Berry curvature dipole.

Abstract

The second-order nonlinear electrical response (NLER) is an intrinsic property of inversion symmetry-broken systems which can provide deep insights into the electronic band structures of atomically thin quantum materials. However, the impact of Fermi surface reconstructions, also known as Lifshitz transitions, on the NLER has remained elusive. We investigated NLER in bilayer graphene (BLG), where the low-energy bands undergo Lifshitz transitions. Here, NLER undergoes a sign change near the Lifshitz transitions even at elevated temperatures $T\gtrsim10~$K. At the band edge, NLER in BLG is modulated by both extrinsic scattering and interfacial-strain-induced intrinsic Berry curvature dipole, both of which can be finely tuned externally by varying doping and interlayer potential. Away from the band edge, BLG exhibits second-order conductivity exceeding $30~\mu$mV$^{-1}\Omega^{-1}$ at 3K higher than any previous report. Our work establishes NLER as a reliable tool to probe Lifshitz transitions in quantum materials.