Lattice parameters and electronic bandgap of orthorhombic potassium sodium niobate KNaNbO from density-functional theory

Nithin Bidaraguppe Ramesh; Falko Schmidt; Arno Schindlmayr

doi:10.1140/epjb/s10051-021-00179-8

2024 Impact factor 1.7

Condensed Matter and Complex Systems

Open Access

Eur. Phys. J. B (2021) 94: 169
https://doi.org/10.1140/epjb/s10051-021-00179-8

Regular Article - Solid State and Materials

Lattice parameters and electronic bandgap of orthorhombic potassium sodium niobate K $_{0.5}$ $_{0.5}$ Na $_{0.5}$ $_{0.5}$ NbO $_{3}$ $_{3}$ from density-functional theory

Nithin Bidaraguppe Ramesh, Falko Schmidt and Arno Schindlmayr^c

Universität Paderborn, Department Physik, 33095, Paderborn, Germany

^c arno.schindlmayr@uni-paderborn.de

Received: 18 December 2020
Accepted: 4 August 2021
Published online: 20 August 2021

Abstract

We perform a theoretical analysis of the structural and electronic properties of sodium potassium niobate K $_{1 - x}$ $_{1-x}$ Na $_{x}$ $_{x}$ NbO $_{3}$ $_{3}$ in the orthorhombic room-temperature phase, based on density-functional theory in combination with the supercell approach. Our results for $x = 0$ $$x=0$$ and $x = 0.5$ $$x=0.5$$ are in very good agreement with experimental measurements and establish that the lattice parameters decrease linearly with increasing Na contents, disproving earlier theoretical studies based on the virtual-crystal approximation that claimed a highly nonlinear behavior with a significant structural distortion and volume reduction in K $_{0.5}$ $_{0.5}$ Na $_{0.5}$ $_{0.5}$ NbO $_{3}$ $_{3}$ compared to both end members of the solid solution. Furthermore, we find that the electronic bandgap varies very little between $x = 0$ $$x=0$$ and $x = 0.5$ $$x=0.5$$ , reflecting the small changes in the lattice parameters.

The affiliation of the authors contained a typo. The correct affiliation is Universität Paderborn.

Copyright comment corrected publication 2021

© The Author(s) 2021. corrected publication 2021

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