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Title: Cooperative effects of strain and electron correlation in epitaxial VO 2 and NbO 2

Abstract

Here, we investigate the electronic structure of the epitaxial VO 2 films in the rutile phase using the density functional theory combined with the slave spin method (DFT+SS). In DFT-SS, the multiorbital Hubbard interactions are added to a DFT-fit tight-binding model, and we employ the slave-spin method to treat the electron correlation. We find that while stretching the system along the rutile c-axis results in a band structure favoring an anisotropic orbital fillings, the electron correlation favors an equal electron filling among t 2g orbitals. These two distinct effects cooperatively induce interesting orbital-dependent redistributions of the electron occupations and the spectral weights, which pushes the strained VO 2 toward an orbital selective Mott transition (OSMT). The simulated single-particle spectral functions are directly compared to V L-edge resonant X-ray photoemission spectroscopy of epitaxial 10 nm VO 2/TiO 2 (001) and (100) strain orientations. Excellent agreement is observed between the simulations and experimental data regarding the strain-induced evolution of the lower Hubbard band. Simulations of rutile NbO 2 under similar strain conditions as VO 2 are performed, and we predict that OSMT will not occur in rutile NbO 2. Our results indicates that the electron correlation in VO 2 is important andmore » can be modulated even in the rutile phase before the Peierls instability sets in.« less

Authors:
 [1]; ORCiD logo [1];  [2]; ORCiD logo [1];  [1]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [5]; ORCiD logo [6];  [7];  [4]; ORCiD logo [1]
  1. Binghamton Univ., Binghamton, NY (United States)
  2. Indian Institute of Technology Chennai (India)
  3. Imperial College London, London (United Kingdom)
  4. Cornell Univ., Ithaca, NY (United States)
  5. Leibniz-Institut fur Kristallzuchtung, Berlin (Germany)
  6. Argonne National Lab. (ANL), Argonne, IL (United States)
  7. Diamond Light Source, Didcot (United Kingdom)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
Air Force Research Laboratory (AFRL), Air Force Office of Scientific Research (AFOSR); National Science Foundation (NSF); USDOE
OSTI Identifier:
1495377
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 125; Journal Issue: 8; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Lee, Wei -Cheng, Wahila, Matthew J., Mukherjee, Shantanu, Singh, Christopher N., Eustance, Tyler, Regoutz, Anna, Paik, H., Boschker, Jos E., Rodolakis, Fanny, Lee, Tien -Lin, Schlom, D. G., and Piper, Louis F. J. Cooperative effects of strain and electron correlation in epitaxial VO2 and NbO2. United States: N. p., 2019. Web. doi:10.1063/1.5052636.
Lee, Wei -Cheng, Wahila, Matthew J., Mukherjee, Shantanu, Singh, Christopher N., Eustance, Tyler, Regoutz, Anna, Paik, H., Boschker, Jos E., Rodolakis, Fanny, Lee, Tien -Lin, Schlom, D. G., & Piper, Louis F. J. Cooperative effects of strain and electron correlation in epitaxial VO2 and NbO2. United States. doi:10.1063/1.5052636.
Lee, Wei -Cheng, Wahila, Matthew J., Mukherjee, Shantanu, Singh, Christopher N., Eustance, Tyler, Regoutz, Anna, Paik, H., Boschker, Jos E., Rodolakis, Fanny, Lee, Tien -Lin, Schlom, D. G., and Piper, Louis F. J. Wed . "Cooperative effects of strain and electron correlation in epitaxial VO2 and NbO2". United States. doi:10.1063/1.5052636.
@article{osti_1495377,
title = {Cooperative effects of strain and electron correlation in epitaxial VO2 and NbO2},
author = {Lee, Wei -Cheng and Wahila, Matthew J. and Mukherjee, Shantanu and Singh, Christopher N. and Eustance, Tyler and Regoutz, Anna and Paik, H. and Boschker, Jos E. and Rodolakis, Fanny and Lee, Tien -Lin and Schlom, D. G. and Piper, Louis F. J.},
abstractNote = {Here, we investigate the electronic structure of the epitaxial VO2 films in the rutile phase using the density functional theory combined with the slave spin method (DFT+SS). In DFT-SS, the multiorbital Hubbard interactions are added to a DFT-fit tight-binding model, and we employ the slave-spin method to treat the electron correlation. We find that while stretching the system along the rutile c-axis results in a band structure favoring an anisotropic orbital fillings, the electron correlation favors an equal electron filling among t2g orbitals. These two distinct effects cooperatively induce interesting orbital-dependent redistributions of the electron occupations and the spectral weights, which pushes the strained VO2 toward an orbital selective Mott transition (OSMT). The simulated single-particle spectral functions are directly compared to V L-edge resonant X-ray photoemission spectroscopy of epitaxial 10 nm VO2/TiO2 (001) and (100) strain orientations. Excellent agreement is observed between the simulations and experimental data regarding the strain-induced evolution of the lower Hubbard band. Simulations of rutile NbO2 under similar strain conditions as VO2 are performed, and we predict that OSMT will not occur in rutile NbO2. Our results indicates that the electron correlation in VO2 is important and can be modulated even in the rutile phase before the Peierls instability sets in.},
doi = {10.1063/1.5052636},
journal = {Journal of Applied Physics},
number = 8,
volume = 125,
place = {United States},
year = {2019},
month = {2}
}

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Works referenced in this record:

Metal-insulator transitions
journal, October 1998

  • Imada, Masatoshi; Fujimori, Atsushi; Tokura, Yoshinori
  • Reviews of Modern Physics, Vol. 70, Issue 4, p. 1039-1263
  • DOI: 10.1103/RevModPhys.70.1039

Metal-insulator transition in vanadium dioxide
journal, June 1975