## Accuracy of Hybrid Functionals with Non-Self-Consistent Kohn–Sham Orbitals for Predicting the Properties of Semiconductors

journal contribution

posted on 21.05.2020, 16:04 by Jonathan M. Skelton, David S. D. Gunn, Sebastian Metz, Stephen C. ParkerAccurately modeling
the electronic structure of materials is a persistent challenge to
high-throughput screening. A promising means of balancing accuracy
against computational cost is non-self-consistent calculations with
hybrid density-functional theory, where the electronic band energies
are evaluated using a hybrid functional from orbitals obtained with
a less demanding (semi)local functional. We have quantified the performance
of this technique for predicting the physical properties of 16 tetrahedral
semiconductors with bandgaps from 0.2 to 5.5 eV. Provided the base
functional predicts a nonmetallic electronic structure, bandgaps within
5% of the PBE0 and HSE06 gaps can be obtained with an order of magnitude
reduction in computing time. The positions of the valence and conduction
band extrema and the Fermi level are well reproduced, enabling calculation
of the band dispersion, density of states, and dielectric properties
using Fermi’s Golden Rule. While the error in the non-self-consistent
total energies is ∼50 meV atom

^{–1}, the energy-volume curves are reproduced accurately enough to obtain the equilibrium volume and bulk modulus with minimal error. We also test the dielectric-dependent scPBE0 functional and obtain bandgaps and dielectric constants to within 2.5% of the self-consistent results, which amounts to a significant improvement over self-consistent PBE0 for a similar computational cost. We identify cases where the non-self-consistent approach is expected to perform poorly and demonstrate that partial self-consistency provides a practical and efficient workaround. Finally, we perform proof-of-concept calculations on CoO and NiO to demonstrate the applicability of the technique to strongly correlated open-shell transition-metal oxides.