Strain and the optoelectronic properties of non-planar phosphorene monolayers

TL;DR

This paper investigates how the non-planar, conical shape of phosphorene monolayers affects their optoelectronic properties, revealing a shape-dependent decrease in the semiconducting gap and proposing methods to analyze local geometry in 2D materials.

Contribution

It demonstrates the impact of non-planar geometry on phosphorene's electronic properties and introduces a classification scheme for 2D materials based on local structural features.

Findings

Semiconducting gap decreases with non-planar shape

Shape effects are consistent across phosphorene allotropes

Proposes methods to determine local geometry from 2D structures

Abstract

Lattice {\em Kirigami}, ultra-light metamaterials, poly-disperse aggregates, ceramic nano-lattices, and two-dimensional (2-D) atomic materials share an inherent structural discreteness, and their material properties evolve with their shape. To exemplify the intimate relation among material properties and the local geometry, we explore the properties of phosphorene --a new 2-D atomic material-- in a conical structure, and document a decrease of the semiconducting gap that is directly linked to its non-planar shape. This geometrical effect occurs regardless of phosphorene allotrope considered, and it provides a unique optical vehicle to single out local structural defects on this 2-D material. We also classify other 2-D atomic materials in terms of their crystalline unit cells, and propose means to obtain the local geometry directly from their diverse two-dimensional structures while bypassing common descriptions of shape that are based from a parametric continuum.