Abstract
Mixed spin-singlet and spin-triplet pairing can occur in noncentrosymmetric superconductors. In this respect, a comprehensive characterization of the noncentrosymmetric superconductor BeAu was carried out. It was established that BeAu undergoes a structural phase transition from a low-temperature noncentrosymmetric FeSi structure type to a high-temperature centrosymmetric structure in the CsCl type at K. The low-temperature modification exhibits a superconducting transition below K. The values of lower ( Oe) and upper ( Oe) critical fields are rather small, confirming that this type-II () weakly coupled () superconductor can be well understood within the Bardeen-Cooper-Schrieffer theory. The muon spin relaxation analysis indicates that the time-reversal symmetry is preserved when the superconducting state is entered, supporting conventional superconductivity in BeAu. From the density functional band structure calculations, a considerable contribution of the Be electrons to the superconducting state was established. On average, a rather small mass renormalization was found, consistent with the experimental data.
3 More- Received 14 November 2017
- Revised 7 December 2017
DOI:https://doi.org/10.1103/PhysRevB.97.014501
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