First-Principle Description of Correlation Effects in Layered Materials

TL;DR

This paper introduces a first-principles method within Density Functional Theory to accurately describe layered materials with both covalent and dispersion interactions, improving understanding of their bonding and vibrational properties.

Contribution

It develops a formalism based on the Adiabatic-Connection Fluctuation-Dissipation Theorem that captures anisotropic bonding in layered materials, addressing limitations of existing functionals.

Findings

Accurately describes in-plane and out-of-plane bonding in hexagonal boron nitride

Successfully models vibrational dynamics at equilibrium and separation

Provides insights into incorporating dispersion interactions into correlation functionals

Abstract

We present a first-principles description of anisotropic materials characterized by having both weak (dispersion-like) and strong covalent bonds, based on the Adiabatic--Connection Fluctuation--Dissipation Theorem within Density Functional Theory. For hexagonal boron nitride the in-plane and out of plane bonding as well as vibrational dynamics are well described both at equilibrium and when the layers are pulled apart. Also bonding in covalent and ionic solids is described. The formalism allows to ping-down the deficiencies of common exchange-correlation functionals and provides insight towards the inclusion of dispersion interactions into the correlation functional.