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arXiv · 2211.10404

Orbital-ordered ferromagnetic insulating state in tensile-strained SrCoO$_{3}$ thin films

Sheng-Chieh Huang·Kanchan Sarkar·Renata M. Wentzcovitch·Han Hsu
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Abstract

At ambient pressure, bulk SrCoO$_{3}$ is a ferromagnetic (FM) metal in cubic perovskite structure. By contrast, magnetic properties of epitaxial SrCoO$_{3}$ thin films, especially at high tensile strain ($\varepsilon \gtrsim 3$\%), remain unclear: Previous calculations had predicted antiferromagnetic (AFM) states more energetically favorable in this regime, but recent experiments indicated a FM insulating state. In this work, using first-principles calculations, we perform an extensive search for the structural, spin, magnetic, and orbital states of SrCoO$_{3}$ thin films. Our calculations indicate that at $0 < \varepsilon \lesssim 2.5$\%, SrCoO$_{3}$ favors a FM half-metallic state with intermediate-spin ($t_{2g}^{5}e_{g}^{1}$-like) Co exhibiting $d^{6}\underline L$ character. At $\varepsilon \gtrsim 2.5$\%, a FM insulating state with high-spin ($t_{2g}^{4}e_{g}^{2}$-like) Co dominates. This FM insulating state is achieved via complicated orbital ordering, cooperative Jahn--Teller distortion, and octahedral tilting about all three crystal axes.

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Sheng-Chieh Huang, Kanchan Sarkar, Renata M. Wentzcovitch, Han Hsu. 2022-11-18. Orbital-ordered ferromagnetic insulating state in tensile-strained SrCoO$_{3}$ thin films. https://arxiv.org/abs/2211.10404

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