Feature-Rich Magnetic Quantization in Sliding Bilayer Graphenes

TL;DR

This paper develops a generalized tight-binding model to study magnetic quantization in sliding bilayer graphenes, revealing how layer shifts dramatically alter Landau levels and magneto-optical properties.

Contribution

It introduces a novel theoretical framework to analyze magnetic quantization in sliding bilayer graphene, highlighting the impact of layer shifts on electronic and optical characteristics.

Findings

Layer shifts cause transformation from Dirac-cone to parabolic bands.

Three types of Landau levels are identified with distinct characteristics.

Undefined LLs show intergroup anti-crossings and many optical absorption peaks.

Abstract

The generalized tight-binding model, based on the subenvelope functions of distinct sublattices, is developed to investigate the magnetic quantization in sliding bilayer graphenes. The relative shift of two graphene layers induces a dramatic transformation between the Dirac-cone structure and the parabolic band structure, and thus leads to drastic changes of Landau levels (LLs) in the spatial symmetry, initial formation energy, intergroup anti-crossing, state degeneracy and semiconductor-metal transition. There exist three kinds of LLs, i.e., well-behaved, perturbed and undefined LLs, which are characterized by a specific mode, a main mode plus side modes, and a disordered mode, respectively. Such LLs are clearly revealed in diverse magneto-optical selection rules. Specially, the undefined LLs frequently exhibit intergroup anti-crossings in the field-dependent energy spectra, and show a large number of absorption peaks without optical selection rules.