Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/102957
Title: Electronic correlations at paramagnetic (001) and (110) NiO surfaces: Charge-transfer and Mott-Hubbard-type gaps at the surface and subsurface of (110) NiO
Authors: Leonov, I.
Biermann, S.
Issue Date: 2021
Publisher: American Physical Society
Citation: Leonov I. Electronic correlations at paramagnetic (001) and (110) NiO surfaces: Charge-transfer and Mott-Hubbard-type gaps at the surface and subsurface of (110) NiO / I. Leonov, S. Biermann. — DOI 10.1103/PhysRevB.103.165108 // Physical Review B. — 2021. — Vol. 103. — Iss. 16. — 165108.
Abstract: We explore the interplay of electron-electron correlations and surface effects in the prototypical correlated insulating material, NiO. In particular, we compute the electronic structure, magnetic properties, and surface energies of the (001) and (110) surfaces of paramagnetic NiO using a fully charge self-consistent DFT+ dynamical mean-field theory method. Our results reveal a complex interplay between electronic correlations and surface effects in NiO, with the electronic structure of the (001) and (110) NiO surfaces being significantly different from that in bulk NiO. We obtain a sizable reduction of the band gap at the surface of NiO, which is most significant for the (110) NiO surface. This suggests a higher catalytic activity of the (110) NiO surface than that of the (001) NiO one. Our results reveal a charge-transfer character of the (001) and (110) surfaces of NiO. Most notably, for the (110) NiO surface we observe a remarkable electronic state characterized by an alternating charge-transfer and Mott-Hubbard character of the band gap in the surface and subsurface NiO layers, respectively. This novel form of electronic order stabilized by strong correlations is not driven by lattice reconstructions but of purely electronic origin. We notice the importance of orbital differentiation of the Ni eg states to characterize the Mott-Hubbard insulating state of the (001) and (110) NiO surfaces. The unoccupied Ni eg surface states are seen to split from the lower edge of the conduction band to form strongly localized states in the fundamental gap of bulk NiO. Our results for the surface energies of the (001) and (110) NiO surfaces show that the (001) facet of NiO has significantly lower energy. This implies that the relative stability of different surfaces, at least from a purely energetic point of view, does not depend on the presence or absence of magnetic order in NiO. © 2021 authors.
Keywords: CATALYST ACTIVITY
CHARGE TRANSFER
ELECTRON CORRELATIONS
ELECTRONIC STRUCTURE
ENERGY GAP
INTERFACIAL ENERGY
MEAN FIELD THEORY
NICKEL
PARAMAGNETISM
DYNAMICAL MEAN-FIELD THEORY
ELECTRON-ELECTRON CORRELATION
ELECTRONIC CORRELATION
ELECTRONIC ORDERING
ELECTRONIC ORIGIN
MOTT-HUBBARD CHARACTER
RELATIVE STABILITIES
STRONG CORRELATION
NICKEL OXIDE
URI: http://hdl.handle.net/10995/102957
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85104407188
PURE ID: 21870133
4ffa06e3-bc11-4a45-82ea-4542f0d124e2
ISSN: 24699950
DOI: 10.1103/PhysRevB.103.165108
metadata.dc.description.sponsorship: We thank S. Backes, S. Panda, D. D. Sarma, and I. A. Abrikosov for valuable discussions. The calculations and theoretical analysis of the electronic properties of (001) and (110) NiO were supported by the state assignment of Minobrnauki of Russia (theme “Electron” No. AAAA-A18-118020190098-5). The calculations of magnetic properties of (001) and (110) NiO were supported by Russian Science Foundation (Project No. 19-72-30043). S.B. acknowledges support from the European Research Council under Grant Agreement No. 617196, Project CORRELMAT, and from IDRIS/GENCI Orsay under Project No. t2021091393.
RSCF project card: 19-72-30043
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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