Diverse Magnetic Quantization in Bilayer Silicene

TL;DR

This paper develops a generalized tight-binding model to explore the complex electronic properties and magnetic quantization phenomena in bilayer silicene under electric and magnetic fields, revealing unique Landau level behaviors.

Contribution

It introduces a comprehensive model capturing the intricate Landau level structures and field-induced effects in bilayer silicene, advancing understanding of its electronic properties.

Findings

Identification of four subgroups of Landau levels with sublattice and spin dominance.

Observation of irregular Landau level energy spectra related to band structure critical points.

Detection of many van Hove singularities and anti-crossings in the density of states and magneto-absorption spectra.

Abstract

The generalized tight-binding model is developed to investigate the rich and unique electronic properties of AB-bt (bottom-top) bilayer silicene under uniform perpendicular electric and magnetic fields. The first pair of conduction and valence bands, with an observable energy gap, displays unusual energy dispersions. Each group of conduction/valence Landau levels (LLs) is further classified into four subgroups, that is, there exist the sublattice- and spin-dominated LL subgroups. The magnetic-field-dependent LL energy spectra exhibit irregular behavior corresponding to the critical points of the band structure. Moreover, the electric field can induce many LL anti-crossings. The main features of the LLs are uncovered with many van Hove singularities in the density-of-states and non-uniform delta-function-like peaks in the magneto-absorption spectra. The feature-rich magnetic quantization directly reflects the geometric symmetries, intra-layer and inter-layer atomic interactions, spin-orbital couplings, and the field effects. The results of this work can be applied to novel designs of $Si$-based nano-electronics and nano-devices with enhanced mobilities.