Two-Dimensional Honeycomb Monolayer of Nitrogen Group Elements and the Related Nano-Structure: A First-Principle Study

TL;DR

This study predicts a new family of two-dimensional honeycomb monolayer materials based on nitrogen group elements, revealing their electronic properties, potential magnetic edge states, and promising applications in various technologies.

Contribution

First-principle calculations of a new family of 2D pnictogen honeycomb monolayers, analyzing their stability, electronic structure, and magnetic edge states.

Findings

Materials have indirect band gaps from 0.43eV to 3.7eV.

Large spin-orbit coupling found in pnictogen lattices.

Potential for spin-polarized ferromagnetic edge states.

Abstract

Because of its novel physical properties, two-dimensional materials have attracted great attention. From first-principle calculations and vibration frequenceis analysis, we predict a new family of two-dimensional materials based on the idea of octet stability: honeycomb lattices of pnictogens (N, P, As, Sb, Bi). The buckled structures of materials come from the sp3 hybridization. These materials have indirect band gap ranging from 0.43eV to 3.7eV. From the analysis of projected density of states, we argue that the s and p orbitals together are sufficient to describe the electronic structure under tight-binding model, and the tight-binding parameters are obtained by fitting the band structures to first-principle results. Surprisingly large on-site spin-orbit coupling is found for all the pnictogen lattices except nitrogen. Investigation on the electronic structures of both zigzag and armchair nanoribbons reveals the possible existence of spin-polarized ferromagnetic edge states in some cases, which are rare in one-dimensional systems. These edge states and magnetism may exist under the condition of high vaccum and low temperature. This new family of materials would have promising applications in electronics, optics, sensors, and solar cells.