Improved polaronic transport under a strong Mott-Hubbard interaction in Cu-substituted NiO

Seong Gon Park, Kyu Hyoung Lee, Jae Hoon Lee, Geukchan Bang, Junghwan Kim, Hee Jung Park, Min Suk Oh, Suyoun Lee, Young Hoon Kim, Young Min Kim, Hideo Hosono, Joonho Bang, Kimoon Lee

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3 Citations (Scopus)


The origin of the electrical and optical properties of Cu-substituted NiO (Cu:NiO) polycrystalline bulks synthesized via a solid-state reaction is reported. The partial substitution of Ni sites with Cu led to a drastic decrease of the electrical resistivity from 7.73 × 108 to 6.51 × 104 Ω·cm and a reduction in the energy for the self-trapping barrier from 0.58 to 0.24 eV in accordance with small polaron hopping conduction. The well-sustained band gap of 3.1 eV and antiferromagnetic transition temperature of 453 K demonstrate that the strength of the electron correlation in NiO can persist even at a high Cu concentration up to 22 atomic percent. Density functional theory calculations confirm that the Cu 3d orbital encourages d-p hybridization between metal cations and oxygen anions at the valence band maximum. As a consequence, this hybridization plays a critical role in improving the polaron hopping efficiency without much suppression of the Mott-Hubbard interaction and thus retaining the wide band gap nature.

Original languageEnglish
Pages (from-to)853-858
Number of pages6
JournalInorganic Chemistry Frontiers
Issue number4
Publication statusPublished - 2020 Feb 21

Bibliographical note

Funding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2019R1A6A1A11055660). It was also partly supported by the MEXT, Element Strategy Initiative to form a research core. M. S. O. acknowledges the National Research Foundation of Korea (NRF) Grant funded by the Ministry of Science and ICT for the First-Mover Program for Accelerating Disruptive Technology Development (NRF-2018M3C1B9088458). S. L. was supported by the National Research Foundation of Korea through NRF-2019M3F3A1A02072175. We also thank Prof. H. Lei for valuable discussions.

Publisher Copyright:
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All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry


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