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Hole doping in a negative charge transfer insulator

Patel, RK and Patra, K and Ojha, SK and Kumar, S and Sarkar, S and Saha, A and Bhattacharya, N and Freeland, JW and Kim, J-W and Ryan, PJ and Mahadevan, P and Middey, S (2022) Hole doping in a negative charge transfer insulator. In: Communications Physics, 5 (1).

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Official URL: https://doi.org/10.1038/s42005-022-00993-1


RENiO3 is a negative charge transfer energy system and exhibits a temperature-driven metal-insulator transition (MIT), which is also accompanied by a bond disproportionation (BD) transition. In order to explore how hole doping affects the BD transition, we have investigated the electronic structure of single-crystalline thin films of Nd1−xCaxNiO3 by synchrotron based experiments and ab-initio calculations. Here we show that for a small value of x, the doped holes are localized on one or more Ni sites around the dopant Ca2+ ions, while the BD state for the rest of the lattice remains intact. The effective charge transfer energy (Δ) increases with Ca concentration and the formation of BD phase is not favored above a critical x, suppressing the insulating phase. Our present study firmly demonstrates that the appearance of BD mode is essential for the MIT of the RENiO3 series.

Item Type: Journal Article
Publication: Communications Physics
Publisher: Nature Research
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Calcium compounds; Calculations; Charge transfer; Electronic structure; Metal insulator boundaries; Nickel compounds; Semiconductor doping; Semiconductor insulator boundaries; Titanium compounds, Ab initio calculations; Charge transfer energy; Charge-transfer insulators; Disproportionations; Electronic.structure; Energy systems; Hole-doping; Metal-insulators transitions; Negative charge; Single-crystalline thin films, Metal insulator transition
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 03 Oct 2022 05:45
Last Modified: 03 Oct 2022 05:45
URI: https://eprints.iisc.ac.in/id/eprint/77010

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