Solid-State Testing of a Van-Der-Waals-Corrected Exchange-Correlation Functional Based on the Semiclassical Atom Theory

Aleksandr Terentjev,Fabio Della Sala,Eduardo Fabiano,Lucian Constantin,José Pitarke,Pietro Cortona

doi:10.3390/computation6010007

Abstract

We extend the SG4 generalized gradient approximation, developed for covalent and ionic solids with a nonlocal van der Waals functional. The resulting SG4-rVV10m functional is tested, considering two possible parameterizations, for various kinds of bulk solids including layered materials and molecular crystals as well as regular bulk materials. The results are compared to those of similar methods, PBE + rVV10L and rVV10. In most cases, SG4-rVV10m yields a quite good description of systems (from iono-covalent to hydrogen-bond and dispersion interactions), being competitive with PBE + rVV10L and rVV10 for dispersion-dominated systems and slightly superior for iono-covalent ones. Thus, it shows a promising applicability for solid-state applications. In a few cases, however, overbinding is observed. This is analysed in terms of gradient contributions to the functional.

Highlights

Non-covalent interactions, especially of the van der Waals type, have been nowadays recognized as fundamental ingredients of any correct and accurate description of complex materials [1,2,3,4,5,6,7,8,9]
The inclusion of non-local rVV10m corrections helps to highly improve with respect to the original SG4 results, especially for lattice constants where SG4 yields a strong overestimation (even with respect to other generalized gradient approximation (GGA); for example, the mean absolute error (MAE) of PBE in this case is 0.674 Å), while a more contained improvement is observed for bulk moduli and interaction energies
This traces back to the fact that by reducing the value of the parameter b, the change in the interaction energies is faster than for the lattice constants while, at the same time, the latter is faster than the change in the bulk modulus

Summary

Introduction

Non-covalent interactions, especially of the van der Waals type, have been nowadays recognized as fundamental ingredients of any correct and accurate description of complex materials [1,2,3,4,5,6,7,8,9]. For non-polar complexes and/or at large intermolecular distances, where covalent interactions are negligible, they play a dominant role. For these reasons, the proper description of dispersion as well as other non-covalent forces has gained a prominent role in computational chemistry [6,10,11,12,13,14,15,16]. One of the most popular computational approaches used in solid-state calculations is Kohn–Sham (KS) density functional theory (DFT) [22] In this context, unlike for chemical applications, Hartree–Fock based, perturbative, and high-level correlated methods show often an excessive

Methods

Results

Conclusion