Stacking and Registry Effects in Layered Materials: The Case of Hexagonal Boron Nitride

TL;DR

This study investigates the interlayer sliding energy landscape of hexagonal boron nitride using density functional theory, revealing the roles of van der Waals and electrostatic forces and proposing a simple geometrical model for the energy landscape.

Contribution

It introduces a simple geometrical model that captures the registry matching and energy landscape of layered h-BN, facilitating modeling of complex layered structures.

Findings

Van der Waals forces anchor layers at a fixed distance.

Electrostatic forces determine stacking mode and sliding energy.

A nearly free-sliding path with bandgap modulations of ~0.6 eV was identified.

Abstract

The interlayer sliding energy landscape of hexagonal boron nitride (h-BN) is investigated via a van der Waals corrected density functional theory approach. It is found that the main role of the van der Waals forces is to "anchor" the layers at a fixed distance, whereas the electrostatic forces dictate the optimal stacking mode and the interlayer sliding energy. A nearly free-sliding path is identified, along which bandgap modulations of ~0.6 eV are obtained. We propose a simple geometrical model that quantifies the registry matching between the layers and captures the essence of the corrugated h-BN interlayer energy landscape. The simplicity of this phenomenological model opens the way to the modeling of complex layered structures, such as carbon and boron nitride nanotubes.