Simulated scanning tunneling microscopy images of few-layer-phosphorus capped by graphene and hexagonal boron nitride monolayers

摘要

Elemental phosphorous is believed to have several stable allotropes that areenergetically nearly degenerate, but chemically reactive. To prevent chemicaldegradation under ambient conditions, these structures may be capped bymonolayers of hexagonal boron nitride ({\em h}-BN) or graphene. We perform {\emab initio} density functional calculations to simulate scanning tunnelingmicroscopy (STM) images of different layered allotropes of phosphorus and studythe effect of capping layers on these images. We find that protectivemonolayers of insulating {\em h}-BN allow to distinguish between the differentstructural phases of phosphorus underneath, even though the images are filteredthrough only nitrogen atoms that appear transparent. No such distinction ispossible for phosphorus films capped by semimetallic graphene that masks theunderlying structure. Our results suggest that the real-space imagingcapability of STM is not hindered by selected capping layers that protectphosphorus surfaces.