Tuning the electronic properties of gated multilayer phosphorene: A self-consistent tight-binding study

TL;DR

This study uses a self-consistent tight-binding approach to analyze how electric fields and charge screening influence the electronic band structure of gated multilayer phosphorene, revealing unique screening effects and layer-dependent band-gap tuning.

Contribution

It introduces a self-consistent tight-binding method accounting for charge screening to study electric-field effects on multilayer phosphorene's electronic properties.

Findings

Charge density and screening anomalies are identified in gated multilayer phosphorene.

Charge screening significantly affects the electric-field tuning of the band gap.

Theoretical results align well with recent experimental observations.

Abstract

By taking account of the electric-field-induced charge screening, a self-consistent calculation within the framework of the tight-binding approach is employed to obtain the electronic band structure of gated multilayer phosphorene and the charge densities on the different phosphorene layers. We find charge density and screening anomalies in single-gated multilayer phosphorene and electron-hole bilayers in dual-gated multilayer phosphorene. Due to the unique puckered lattice structure, both intralayer and interlayer charge screenings are important in gated multilayer phosphorene. We find that the electric-field tuning of the band structure of multilayer phosphorene is distinctively different in the presence and absence of charge screening. For instance, it is shown that the unscreened band gap of multilayer phosphorene decreases dramatically with increasing electric-field strength. However, in the presence of charge screening, the magnitude of this band-gap decrease is significantly reduced and the reduction depends strongly on the number of phosphorene layers. Our theoretical results of the band-gap tuning are in good agreement with recent experiments.