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This content will become publicly available on December 28, 2018

Title: Electronic properties of doped and defective NiO: A quantum Monte Carlo study

NiO is a canonical Mott (or charge-transfer) insulator and as such is notoriously difficult to describe using density functional theory (DFT) based electronic structure methods. Doped Mott insulators such as NiO are of interest for various applications but rigorous theoretical descriptions are lacking. Here, we use quantum Monte Carlo methods, which very accurately include electron-electron interactions, to examine energetics, charge- and spin-structures of NiO with various point defects, such as vacancies or substitutional doping with potassium. The formation energy of a potassium dopant is significantly lower than for a Ni vacancy, making potassium an attractive monovalent dopant for NiO. We compare our results with DFT results that include an on-site Hubbard U (DFT+U) to account for correlations and find relatively large discrepancies for defect formation energies as well as for charge and spin redistributions in the presence of point defects. Finally, it is unlikely that single-parameter fixes of DFT may be able to obtain accurate accounts of anything but a single parameter, e.g., band gap; responses that, maybe in addition to the band gap, depend in subtle and complex ways on ground state properties, such as charge and spin densities, are likely to contain quantitative and qualitative errors.
Authors:
 [1] ;  [1] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [2] ;  [1] ;  [4]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science & Technology Division
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division; Northwestern Univ., Evanston, IL (United States). Inst. for Science and Engineering
Publication Date:
Grant/Contract Number:
AC02-06CH11357; AC05-00OR22725; AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Physical Review Materials
Additional Journal Information:
Journal Volume: 1; Journal Issue: 7; Journal ID: ISSN 2475-9953
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Quantum Monte Carlo; Density Functional Theory; DFT; Point Defects
OSTI Identifier:
1416980
Alternate Identifier(s):
OSTI ID: 1416430; OSTI ID: 1422575