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The 27th AIRAPT International Conference on High Pressure Science and Technology
Abstract

Investigação


Superconductivity at 250 K in lanthanum hydride under high pressures

Authors:
Alexander Drozdov (MPIC - Max Planck Institute for Chemistry)

Abstract:

Superconductivity at 250 K in lanthanum hydride under high pressures

A. P.  Drozdov1*, P. P. Kong1, V. S. Minkov1, S. P. Besedin1, M. A. Kuzovnikov1,6, S. Mozaffari2, L. Balicas2,  F. F. Balakirev3, D. E. Graf2, V. B. Prakapenka4, E. Greenberg4, D. A. Knyazev1, M. Tkacz5, and M. I. Eremets1

 

1Max-Planck Institut für Chemie, Hahn-Meitner Weg 1, 55128 Mainz, Germany

2National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA

3NHMFL, Los Alamos National Laboratory, MS E536, Los Alamos, New Mexico 87545, USA

4Center for Advanced Radiation Sources, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois, 60637, USA

5Institute of Physical Chemistry PAS, Kasprzaka 44/ 52, 01-224 Warsaw, Poland

6Institute of Solid State Physics RAS, Chernogolovka, Moscow District, 142432 Russia

 

Keywords: high pressure, superconductivity, hydrides.

*e-mail: a.drozdov@mpic.de

 

The discovery of superconductivity at 203 K in H3S [1] returned attention to conventional superconductors whose properties can be described by the Bardeen-Cooper-Schrieffer (BCS) and the Migdal-Eliashberg theories. The DFT-based calculations suggested a new family of hydrides possessing a clathrate-like structure, where the host atom (Ca, Y, La) is at the center of the cage formed by hydrogen atoms [2-4]. These superhydrides can be considered to be doped versions of metallic hydrogen and therefore are expected to have high Tcs. Indeed, DFT predicts a Tc of 235 K at 150 GPa for CaH62, Tc = 305–326 K at 250 GPa5 (or 303 K at 400 GPa) for YH10, and a Tc ~ 280 K at ~ 200 GPa for LaH10.

In the present work, we performed an extensive search for superconductivity in the lanthanum hydrides. The samples were synthesized directly from lanthanum or LaH3 and hydrogen under high pressure. We have found superconductivity with a record Tc ~ 250 K within the Fm-3m structure of LaH10 at a pressure P ~ 170 GPa [6]. We demonstrated the existence of superconductivity at 250 K through the observation of zero-resistance, the isotope effect, and the decrease of Tc under an external magnetic field. This jump of ~50 K above the previous Tc record of 203 K1 is encouraging for achieving room temperature superconductivity in the near future.

 

  1. A. P. Drozdov, M. I. Eremets, I. A. Troyan, V. Ksenofontov, and S. I. Shylin, Nature 2015, 525, 73.
  2. Wang, H., Tse, J. S., Tanaka, K., Iitaka, T. i. & Ma, Y. Superconductive sodalite-like clathrate calcium hydride at high pressures. PNAS 109, 6463–6466 (2012).
  3. Peng, F. et al. Hydrogen Clathrate Structures in Rare Earth Hydrides at High Pressures: Possible Route to Room-Temperature Superconductivity. Phys. Rev. Lett. 119 107001 (2017).
  4. Liu, H. et al. Dynamics and superconductivity in compressed lanthanum
  5. Liu, H., Naumov, I. I., Hoffmann, R., Ashcroft, N. W. & Hemley, R. J. Potential high-Tc superconducting lanthanum and yttrium hydrides at high pressure. PNAS 114, 6990 (2017).
  6. Drozdov, A.P., Kong, P.P., Minkov, V.S., Besedin, S.P., Kuzovnikov, M.A., Mozaffari, S., Balicas, L., Balakirev, F., Graf, D., Prakapenka, V.B. and Greenberg, E., 2018. Superconductivity at 250 K in lanthanum hydride under high pressures. arXiv preprint arXiv:1812.01561