Eur. Phys. J. B (2018) 91: 183
https://doi.org/10.1140/epjb/e2018-90116-7

Regular Article

Studying the occupied and unoccupied electronic structure of LaCoO₃ by using DFT+embedded DMFT method with the calculated value of U

¹ School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India
² School of Engineering, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh 175005, India

^a e-mail: dutta.paromita1@gmail.com

Received: 2 March 2018
Received in final form: 1 June 2018
Published online: 3 August 2018

Abstract

In this work, we present a systematic study of the occupied and unoccupied electronic states of LaCoO₃ compound using DFT, DFT+U and DFT+embedded DMFT methods. The value of U used here is evaluated by using constrained DFT method and found to be ~6.9 eV. It is found that DFT result has limitations with energy positions of PDOS peaks due to its inability of creating a hard gap although the DOS distribution appears to be fine with experimental attributes. The calculated value of U is not an appropriate value for carrying out DFT+U calculations as it has created an insulating gap of ~1.8 eV with limitations in redistribution of DOS which is inconsistent with experimental spectral behavior for the occupied states mainly. However, this value of U is found to be an appropriate one for DFT+embedded DMFT method which creates a gap of ~1.1 eV. The calculated PDOS of Co 3d, La 5d, La 4f and O 2p states are giving a remarkably good explanation for the occupied and unoccupied states of the experimental spectra in the energy range ~–9.0 eV to ~12.0 eV.