Accurate Electron-phonon Interactions from Advanced Density Functional Theory

TL;DR

This paper demonstrates that the advanced r2scan density functional accurately models electron-phonon interactions in complex materials, improving predictions of superconductivity and phonon properties without empirical parameters.

Contribution

It introduces the use of r2scan DFT for precise, parameter-free modeling of electron-phonon interactions in transition-metal oxides and superconductors.

Findings

r2scan captures strong EPC effects in CoO and NiO.

Improved modeling of phonon-mediated superconductivity in MgB₂.

Enhanced electronic and phonon property predictions over traditional functionals.

Abstract

Electron-phonon coupling (EPC) is key for understanding many properties of materials such as superconductivity and electric resistivity. Although first principles density-functional-theory (DFT) based EPC calculations are used widely, their efficacy is limited by the accuracy and efficiency of the underlying exchange-correlation functionals. These limitations become exacerbated in complex $d$- and $f$-electron materials, where beyond-DFT approaches and empirical corrections, such as the Hubbard $U$, are commonly invoked. Here, using the examples of CoO and NiO, we show how the efficient r2scan density functional correctly captures strong EPC effects in transition-metal oxides without requiring the introduction of empirical parameters. We also demonstrate the ability of r2scan to accurately model phonon-mediated superconducting properties of the main group compounds (e.g., MgB$_2$), with improved electronic bands and phonon dispersions over those of traditional density functionals. Our study provides a pathway for extending the scope of accurate first principles modeling of electron-phonon interactions to encompass complex $d$-electron materials.