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

Abstract

Accurately modeling the electronic structure of materials is a persistent challenge to highthroughput screening. A promising means of balancing accuracy against computational cost are 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 sixteen tetrahedral semiconductors with bandgaps from 0.2-5.5 eV. Provided the base functional predicts a non-metallic 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, further 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 amount 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.

Cost-Effective High-Throughput Calculation Based on Hybrid Density Functional Theory: Application to Cubic, Double, and Vacancy-Ordered Halide Perovskites

“…Hybrid DFT calculations have been generally considered to be not ideal for high-throughput calculation because of the heavier computational cost than local or semilocal functional calculations. In the meantime, recent studies have proposed several methods to reduce the computational cost to make it available for high-throughput calculations. , When the electronic structure is the only concern, the non-self-consistent field (NSCF) calculation can be employed. Here we emphasize that it is not another NSCF calculation keeping the charge density to obtain the electronic band structure using the local or semilocal functionals.…”

“…In other words, the maximum number of electronic self-consistency steps is set to be 1 (NELM tag in VASP equals 1). Unless the material is calculated to be metallic in the former calculation, the NSCF method predicts the band gap with high accuracy at a lower computation cost , as local and semilocal calculations provide a good prediction of the wave function.…”

Improving results by improving densities: Density-corrected density functional theory

“…As we have seen, the concept of density-driven errors is becoming widespread in the chemical literature and to a lesser extent, in the materials world. [102,103,104] Moreover, increasing numbers of authors are finding that the selective use of HF densities does indeed significantly reduce density-driven errors. In this section, we list some of the more obvious limitations of the current theory and also where it might be expanded.…”

Density-corrected DFT explained: Questions and answers

“…[69] Similar cost reduction strategies have been applied to semiconductor calculations. [70] In future years, where and how DC-DFT can be useful in surface and material science needs to be further explored.…”