Nicole Kirchner-Hall^1*, Wayne Zhao¹, Yihuang Xiong¹, Iurii Timrov², Ismaila Dabo¹

1 Department of Materials Science and Engineering and the Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

2 Theory and Simulation of Materials (THEOS) and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland

* Corresponding authors emails: nek5091@psu.edu

DOI10.24435/materialscloud:jx-fp [version v1]

Publication date: Mar 02, 2021

How to cite this record

Nicole Kirchner-Hall, Wayne Zhao, Yihuang Xiong, Iurii Timrov, Ismaila Dabo, Extensive benchmarking of DFT+U calculations for predicting band gaps, Materials Cloud Archive 2021.36 (2021), doi: 10.24435/materialscloud:jx-fp.

Description

Accurate computational predictions of band gaps are of practical importance to the modeling and development of semiconductor technologies, such as (opto)electronic devices and photoelectrochemical cells. Among available electronic-structure methods, density-functional theory (DFT) with the Hubbard U correction (DFT+U) applied to band edge states is a computationally tractable approach to improve the accuracy of band gap predictions beyond that of DFT calculations based on (semi)local functionals. At variance with DFT approximations, which are not intended to describe optical band gaps and other excited-state properties, DFT+U can be interpreted as an approximate spectral-potential method when U is determined by imposing the piecewise linearity of the total energy with respect to electronic occupations in the Hubbard manifold (thus removing self-interaction errors in this subspace), thereby providing a (heuristic) justification for using DFT+U to predict band gaps. However, it is still frequent in the literature to determine the Hubbard U parameters semiempirically by tuning their values to reproduce experimental band gaps, which ultimately alters the description of other total-energy characteristics. Here, we present an extensive assessment of DFT+U band gaps computed using self-consistent ab initio U parameters obtained from density-functional perturbation theory to impose the aforementioned piecewise linearity of the total energy. The study is carried out on 20 compounds containing transition-metal or p-block (group III-IV) elements, including oxides, nitrides, sulfides, oxynitrides, and oxysulfides. By comparing DFT+U results obtained using nonorthogonalized and orthogonalized atomic orbitals as Hubbard projectors, we find that the predicted band gaps are extremely sensitive to the type of projector functions and that the orthogonalized projectors give the most accurate band gaps, in satisfactory agreement with experimental data. This work demonstrates that DFT+U may serve as a useful method for high-throughput workflows that require reliable band gap predictions at moderate computational cost.

Materials Cloud sections using this data

Files

File name	Size	Description
Benchmark_calculations.zip MD5md5:4ef75258a9182b19473bb7d5726d2207	5.0 GiB	Please reference the README.txt files in each of the folders for explanations of the calculations contained within each folder.
README.txt MD5md5:f6d8f48fb9cc13d99594b8d4b01c663c	1.7 KiB	README.txt explaining the contents of 'Benchmark_calculations.zip'

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External references

Keywords

DFT+U band gap Hubbard correction Lowdin orthogonalization self-interaction SNSF MARVEL/OSP