Two-gap superconductivity in the noncentrosymmetric La${}_3$Se${}_4$ compound

Abstract

Point-contact Andreev reflection spectroscopy at low temperatures and high magnetic fields has been performed on a noncentrosymmetric La${}_3$Se${}_4$ superconductor with a critical temperature $T_c$ = 8 K. Two superconducting energy gaps ${\Delta }_1$ and ${\Delta }_2$ with $2{\Delta }_1/k_B{T}_c$ ~ 5.8 and $2{\Delta }_2/k_B{T}_c$ ~ 2.3, are directly observed in some of the spectra. The temperature and magnetic field effects help to resolve a two-gap structure even on the most frequent spectra where at low temperatures only a single gap is apparent, reflected in a pair of maxima around the zero bias. Two-gap superconductivity consistently with the point contact Andreev reflection spectroscopy is also supported by the heat capacity and the Hall probe magnetization measurements.

13 pages including Supplemental Material. 6 figures in the article and 3 figures in the Supplemental Material

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Cited by in corpus (1)

• Emergence of Superconductivity at 20 K in Th${}_3$P${}_4$-type In${}_{3-x}$S${}_4$ Synthesized by Diamond Anvil Cell with Boron-doped Diamond Electrodes