Tunable Lifshitz Transitions and Multiband Transport in Tetralayer Graphene

TL;DR

This study demonstrates multiple Lifshitz transitions and multiband transport in tetralayer graphene, revealing complex electronic behavior tunable by charge density and electric field, with implications for 2D material physics.

Contribution

It provides experimental evidence of tunable Lifshitz transitions and multiband transport in tetralayer graphene, a novel observation in this material system.

Findings

Non-monotonic conductivity dependence on charge density and electric field

Observation of anomalous quantum Hall sequences

Landau level crossings evolving with parameters

Abstract

As the Fermi level and band structure of two-dimensional materials are readily tunable, they constitute an ideal platform for exploring Lifshitz transition, a change in the topology of a material's Fermi surface. Using tetralayer graphene that host two intersecting massive Dirac bands, we demonstrate multiple Lifshitz transitions and multiband transport, which manifest as non-monotonic dependence of conductivity on charge density n and out-of-plane electric fieldD, anomalous quantum Hall sequences and Landau level crossings that evolve with n, D and B.