Importance of the Hubbard correction on the thermal conductivity calculation of strongly correlated materials: a case study of ZnO

Abstract

The wide bandgap semiconductor, ZnO, has gained interest recently as a promising option for use in power electronics such as thermoelectric and piezoelectric generators, as well as optoelectronic devices. Though much work has been done to improve its electronic properties, relatively little is known of its thermal transport properties with large variations in measured thermal conductivity. In this study, we examine the effects of a Hubbard corrected energy functional on the lattice thermal conductivity of wurtzite ZnO calculated using density functional theory and an iterative solution to the Boltzmann transport equation. Showing good agreement with existing experimental measurements, and with a detailed analysis of the mode-dependence and phonon properties, the results from this study highlight the importance of the Hubbard correction in calculations of thermal transport properties of materials with strongly correlated electron systems.

Effects of Hubbard term correction on the structural parameters and electronic properties of wurtzite ZnO

“…Compared to LDA, LDA+U overestimates the gamma point frequencies by about 10% for the higher lying modes. It is noticed that gamma phonon modes frequencies in good agreement with experiment is reproduced by PBE+U calculations [23,24]. The choice of change correlation functional plays a huge role in the accurate description of the underlying electrostatics and vibrational properties of a system.…”

Effects of Van der Waals Interaction and Hubbard Term Correction on First Principles Calculations of Structural and Lattice Dynamical Properties of AgCl

“…Hubbard U term (PBE+U) is only a correction to traditional density functional theory and account for the over-hybridization and localization of electron orbitals (Anisimov et al, 1991). Assuming that implementing a Hubbard U term to the PBE (PBE+U) (Anisimov et al, 1991) have a significant effect on strongly correlated d or f electron (Zhang and Jiang, 2019;Jiang, 2018;Jossou et al, 2017;Consiglio and Tian, 2016;Tolba et al, 2018), calculations were performed with and without U term. For PBE+U calculations, following (Gao et al, 2018), Ueff =U-J=5 eV value was applied to the d orbitals of Ag.…”

Lattice thermal conductivity of ZnO: experimental and theoretical studies

“…This The failure of the conventional DFT technique in calculating the electronic structure with the experimentally observed band gap of ZnO is due to the ignorance of valence electron localization. 29 The relative localization of electrons around the atomic species is analyzed from the 2D electron localization function (ELF) projected along the (110) plane of the 32-atom ZnO supercell. The ELF approaches zero in the absence of a significant density of localized electrons, whereas for the highly localized electronic population, it corresponds to unity.…”