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arXiv · 2302.09588

The origin of strain-induced stabilisation of superconductivity in the lanthanum cuprates

Christopher Keegan·Mark S. Senn·Nicholas C. Bristowe·Arash A. Mostofi
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Abstract

Suppression of superconductivity in favour of a striped phase, and its coincidence with a structural transition from a low-temperature orthorhombic (LTO) to a low-temperature tetragonal (LTT) phase, is a ubiquitous feature of hole-doped lanthanum cuprates. We study the effect of anisotropic strain on this transition using density-functional theory on both La$_2$CuO$_4$ and the recently-synthesised surrogate La$_2$MgO$_4$ to decouple electronic and structural effects. Strikingly, we find that compressive strain applied diagonally to the in-plane metal-oxygen bonds dramatically stabilises the LTO phase. Given the mutual exclusivity of 3D superconductivity and long-range static stripe order, we thereby suggest a structural mechanism for understanding experimentally-observed trends in the superconducting $T_{\mathrm{c}}$ under uniaxial pressure, and suggest principles for tuning it.

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Christopher Keegan, Mark S. Senn, Nicholas C. Bristowe, Arash A. Mostofi. 2023-02-19. The origin of strain-induced stabilisation of superconductivity in the lanthanum cuprates. https://arxiv.org/abs/2302.09588

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