The effect of electronically-induced lattice distortions on the structural distortions in layered lanthanum cuprates.

ORAL

Abstract

The Jahn-Teller active La(2-x)Ba(x)CuO4 system undergoes a phase transition from a low-temperature orthorhombic (LTO) to a low-temperature tetragonal (LTT) phase at doping values centred around x = 0.125. The LTT phase correlates with a dramatic suppression of superconductivity, neither of which are observed in the Sr-doped lanthanum cuprate. In this work we use density-functional theory calculations to understand the extent to which structural distortions arising from the Jahn-Teller effect induce a symmetry-breaking distortion in the Ba-doped system but not in the Sr-doped system. We find that the relative stability of the LTT and LTO phases is sensitive to the magnitude of the Jahn-Teller distortion and the average A-site ionic radius, which helps explain the differences between the phase diagrams of the Ba- and Sr-doped systems.

*This work was supported through a studentship in the Centre for Doctoral Training on Theory and Simulation of Materials at Imperial College London funded by the EPSRC (EP/L015579/1). We are grateful to the UK Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/P020194/1 and EP/T022213/1).

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Presenters

  • Christopher Keegan

    • Imperial College London

Authors

  • Christopher Keegan

    • Imperial College London

  • Mark Senn

    • Department of Chemistry, University of Warwick
    • Chemistry, University of Warwick

  • Nicholas Bristowe

    • Durham University
    • Physics, University of Durham
    • Centre for Materials Physics, Durham University

  • Arash A Mostofi

    • Imperial College London
    • Departments of Materials and Physics, and the Thomas Young Centre for Theory and Simulation of Materials, Imperial College London