Landau quantization of Dirac fermions in graphene and its multilayer

TL;DR

This review discusses the experimental observation of Landau quantization in graphene and multilayer graphene, highlighting how magnetic fields, strain, and defects influence their unique electronic spectra and physical properties.

Contribution

The paper provides a comprehensive review of experimental findings on Landau quantization in graphene, emphasizing the effects of layer number, stacking, strain, and defects.

Findings

Distinct Landau-level spectra observed in different graphene layers

Landau quantization can be used to identify layer number and stacking order

Strain and defects significantly modify Landau quantization phenomena

Abstract

When electrons are confined in a two dimensional (2D) system, typical quantum mechanical phenomena such as Landau quantization can be detected. Graphene systems, including the single atomic layer and few-layer stacked crystals, are ideal 2D materials for studying a variety of quantum mechanical problems. In this article, we review the experimental progress in the unusual Landau quantized behaviors of Dirac fermions in monolayer and multilayer graphene by using scanning tunneling microscopy(STM) and scanning tunneling spectroscopy(STS). Through STS measurement of the strong magnetic fields, distinct Landau-level spectra and rich level splitting phenomena are observed in different graphene layers. These unique properties provide an effective method for identifying the number of layers, as well as the stacking orders, and investigating the fundamentally physical phenomena of graphene. Moreover, in the presence of a strain and charged defects, the Landau quantization of graphene can be significantly modified, leading to unusual spectroscopic and electronic properties.