Ultrafast dynamics evidence of strong coupling superconductivity in LaH10±δ

Y L Wu; X H Yu; J Z L Hasaien; Fang Hong; P F Shan; Z Y Tian; Y N Zhai; J P Hu; J G Cheng; Jimin Zhao

doi:10.1038/s41467-024-53103-w

Ultrafast dynamics evidence of strong coupling superconductivity in LaH_10±δ

Nat Commun. 2024 Nov 8;15(1):9683. doi: 10.1038/s41467-024-53103-w.

Authors

Y L Wu^#^{1

2}, X H Yu^#^{1

3

4}, J Z L Hasaien^#^{1

3}, Fang Hong^{5

6}, P F Shan^{1

3}, Z Y Tian¹, Y N Zhai^{1

3}, J P Hu^{1

3

7}, J G Cheng^{8

9}, Jimin Zhao^{10

11

12}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
² Hebei Key Laboratory of Microstructural Material Physics, School of Science, Yanshan University, Qinhuangdao, China.
³ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
⁴ Songshan Lake Materials Laboratory, Dongguan, Guangdong, China.
⁵ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China. [email protected].
⁶ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China. [email protected].
⁷ New Cornerstone Science Laboratory, Beijing, China.
⁸ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China. [email protected].
⁹ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China. [email protected].
¹⁰ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China. [email protected].
¹¹ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China. [email protected].
¹² Songshan Lake Materials Laboratory, Dongguan, Guangdong, China. [email protected].

^# Contributed equally.

Abstract

Recently, tremendous research interest has been aroused in clathrate superhydrides. However, their microscopic properties, especially the superconducting (SC) gap and electron-phonon coupling (EPC) strength, are largely unexplored experimentally. Here, we investigate the time-resolved ultrafast spectroscopy of a superconductor LaH_10±δ under an ultrahigh pressure of 165 GPa. By analyzing the ultrafast dynamics of the quasiparticles, we experimentally obtain the SC gap Δ(0) = 53 ± 5 meV, revealing a gap ratio 2Δ(0)/k_BT_c = 5.6 and a gap parameter ϑ = 1.95. Significantly, we experimentally estimate $λ ⟨ Ω^{2} ⟩$ = (2.4 ± 0.1) × 10⁴ (meV)², which corresponds to an EPC strength λ = 2.58 ± 0.11. These results together provide direct experimental evidence that strong EPC is responsible for the near-room-temperature superconductivity in clathrate superhydrides. Our investigation significantly advances the experimental exploration of superhydrides, and contributes to the ultrafast dynamics investigations of quantum materials under high pressures.