Engineering the Mott State of Cuprates for High-Temperature Superconductivity

O. Ivashko, M. Horio, W. Wan, N. B. Christensen, D. E. McNally, E. Paris, Y. Tseng, N. E. Shaik, H. M. Rønnow, H. I. Wei, C. Adamo, C. Lichtensteiger, M. Gibert, M. R. Beasley, K. M. Shen, J. M. Tomczak, T. Schmitt, and J. Chang

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Received Date: 31st July 2018

Unconventional superconductivity is often soft and tunable. To optimise Tc, the sweet spot for a monolayer of FeSe is, for example, uniquely bound to titanium-oxide substrates. By contrast for La2−xSrxCuO4 thin films, such substrates are sub-optimal and the highest transition temperature is instead obtained using LaSrAlO4. An outstanding challenge is thus to understand what are the optimal conditions for superconductivity in thin films and, eventually, how to realise them. Here we demonstrate, by a combination of x-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) spectroscopy, how the Coulomb and magnetic-exchange interaction of prototypical La2CuO4 thin films can be enhanced by compressive strain. Our experiments and theoretical calculations establish that the substrate producing the largest Tc also generates the largest nearest neighbour hopping integral, Coulomb and magnetic-exchange interaction. We hence suggest optimising the parent Mott state as a strategy for enhancing the superconducting transition temperature in cuprates.

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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

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