Superconductivity in thin film metal hydrides at megabar pressures

ORAL

Abstract

Metal hydrides at high pressures offer the prospect of finding superconductivity at room temperature [1, 2]. Our group at the University of Bristol has confirmed independently the presence of superconductivity below 200K in bulk H3S [3]. We have also developed a new approach to synthesise hydride superconductors from an elemental thin film directly evaporated on the diamond anvil and ammonia borane (NH3BH3) as a hydrogen donor [4, 5]. This method facilitates the preparation of hydrides at megabar pressure and increases our success rate. In this talk, I will demonstrate the synthesis of YH4 and LaH4 thin films, which by having a lower Tc ≈ 40-80K (depending on pressure) allow us to study the critical field Hc2(T) over the full temperature range. I will present crystal structures obtained from x-ray diffraction, resistivity measurements as a function of temperature and magnetic field, and Hc2(T) extracted from DC and pulsed magnetic field measurements. I will also discuss remaining challenges in sample synthesis.



References

[1] A. P. Drozdov, et al. Nature 525, 73 (2015)

[2] A. P. Drozdov, et al. Nature 569, 528 (2019)

[3] I. Osmond et al. Phys. Rev. B 105, L220502 (2022)

[4] J. Buhot et al. Physical Review B 102, 104508 (2020)

[5] S. Cross et al. Physical Review B 109, L020503 (2024)

*This research has been supported by the ERC (Grant No.715262-HPSuper) and EPSRC (Grant No. EP/V048759/1).J. Buhot acknowledges support from the UKRI in the form of an EPSRC Open Fellowship (Grant No. EP/Z533555/1).O. Lord acknowledges support from the Royal Society in the form of a University Research Fellowship (Grant No. UF150057) and associated grants.

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Publication: I. Osmond et al. Phys. Rev. B 105, L220502 (2022)
J. Buhot et al. Physical Review B 102, 104508 (2020)
S. Cross et al. Physical Review B 109, L020503 (2024)

Presenters

  • Jonathan Buhot

    • University of Bristol

Authors

  • Jonathan Buhot

    • University of Bristol

  • Sam Cross

    • University of Bristol

  • Owen Moulding

    • Institut NEEL CNRS

  • Israel Osmond

    • The University of Edinburgh

  • Annabelle Brooks

    • University of Oxford

  • William Thomas

    • University of Bristol

  • Xiaojiao Liu

    • Diamond Light Source

  • Annette Kleppe

    • Diamond Light Source

  • Nico Giordano

    • Deutsches Elektronen-Synchrotron DESY

  • Timofey Fedotenko

    • Deutsches Elektronen-Synchrotron DESY

  • Hanns-Peter Liermann

    • DESY

  • Björn Wehinger

    • ESRF

  • Mohamed Mezouar

    • European Synchrotron Radiation Facility

  • Alix McCollam

    • University College Cork

  • Toni Helm

    • Helmholtz-Zentrum Dresden-Rossendorf

  • Oliver Lord

    • University of Bristol

  • Sven Friedemann

    • University of Bristol