Speaker
Description
Non-centrosymmetric superconducting materials represent a class of materials with existing unconventional properties. Thanks to the broken inversion symmetry these materials can exhibit properties such as mixed-parity pairing and very high upper critical magnetic field. Point-Contact Andreev reflection spectroscopy can be a great technique for studying these phenomena. Point-contact spectroscopy measurements at low temperatures and high magnetic fields have been performed on a non-centrosymmetric La$_3$Se$_4$ superconductor with a critical temperature $T_{c} = 8$ K. Two superconducting energy gaps $\Delta_{1}$ and $\Delta_{2}$, with $2\Delta_{1}/k_{B}T_{c} \sim 5.8$ and $2\Delta_{2}/k_{B}T_{c} \sim 2.3$, 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. The claim of two-gap superconductivity is also supported by the heat capacity and the Hall probe magnetization measurements.
Acknowledgements
This work was supported by the Slovak Research and Development Agency under Contract No. APVV-20-0425, by the Science Grant Agency project VEGA 2/0073/24, COST action No. CA21144 (SUPERQUMAP), Slovak Academy of Sciences Project No. IMPULZ IM-2021–42. The work in Dresden was supported by the German Research Foundation (DFG) within the Walter Benjamin research Grant No. NA 2012/1-1.
