Isotope Effect on Superconductivity in Solid Hydrogen

ORAL

Abstract

After decades of experimental progress on diamond anvil cells, researchers are able to squeeze solid hydrogen to pressures up to 450 GPa. In particular, two recent experiments by Loubeyre et al. employed infrared measurements to track the direct band gap and vibron frequency of hydrogen up to ~425 GPa [1] and deuterium up to ~460 GPa [2]. We previously argued that observed data is consistent with the molecular C2/c-24 phase, which can explain the observed behavior up to ~425 GPa and above without requiring a structural phase transition [3]. The observations on deuterium strengthen our interpretation. We also previously reported the predicted superconducting properties of this phase as well as the other three most likely phases (Cmca-12, Cmca-4 and I41/amd-2) in the 400–500 GPa range [4,5]. In this work, we employ a Wannier function-based dense k-point and q-point sampling to compute the electron-phonon coupling and superconducting properties of solid deuterium in these four phases. In addition to their predictive nature, our findings will help future experiments distinguish between the candidate crystal phases.

[1] P. Loubeyre, F. Occelli, P. Dumas, Nature 577, 7792 (2020).

[2] P. Loubeyre, F. Occelli, P. Dumas, Phys. Rev. Lett. 129, 035501 (2022).

[3] M. Dogan, S. Oh, M. L. Cohen, J. Phys.: Condens. Matter 33, 03LT01 (2020).

[4] M. Dogan, S. Oh, M. L. Cohen, Phys. Rev. B 105, L020509 (2022).

[5] M. Dogan, S. Oh, M. L. Cohen, J. Phys.: Condens. Matter 34, 15LT01 (2022).

*This work was supported by the Department of Energy under Contract No. DE-AC02-05-CH11231 within the Theory of Materials program (KC2301), which supported the electronic structure calculations, the National Science Foundation under Grant No. DMR-1926004, which supported the calculations of vibrational properties, and the "Characteristic Science Applications for the Leadership Class Computing Facility" project, supported by National Science Foundation award #2139536, which provided the support for the electron–phonon calculations.

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Publication: M. Dogan, S. Oh, and M. L. Cohen, Observed Metallization of Hydrogen Interpreted as a Band Structure Effect, J. Phys.: Condens. Matter 33, 03LT01 (2020).
M. Dogan, S. Oh, and M. L. Cohen, Prediction of High-Temperature Superconductivity in C2/c24 Solid Hydrogen, Phys. Rev. B 105, L020509 (2022).
M. Dogan, S. Oh, and M. L. Cohen, High Temperature Superconductivity in the Candidate Phases of Solid Hydrogen, J. Phys.: Condens. Matter 34, 15LT01 (2022).
M. Dogan, J. R. Chelikowsky, M. L. Cohen, manuscript in progress.

Presenters

  • Mehmet Dogan

    • University of Texas at Austin

Authors

  • Mehmet Dogan

    • University of Texas at Austin

  • James R Chelikowsky

    • University of Texas at Austin

  • Marvin L Cohen

    • University of California, Berkeley