Noncentrosymmetric Superconductor BeAu

Published: January 04, 2018

Author(s)

A. Amon, E. Svanidze, R. Cardoso-Gil, M. N. Wilson, H. Rosner, M. Bobnar, W. Schnelle, Jeffrey W. Lynn, R. Gumeniuk, C. Hennig, G. M. Luke, H. Borrmann, A. Leithe-Jasper, Yu Grin

Abstract

In noncentrosymmetric superconductors mixed spin-singlet and spin-triplet pairing can occur. In this work, physical properties of the noncentrosymmetric superconductor, BeAu, were investigated. It was established that BeAu undergoes a structural phase transition from a low-temperature non-centrosymmetric FeSi structure type to a high-temperature structure in the CsCl type at Ts= 860 K. The low-temperature modification exhibits a superconducting transition below Tc = 3.3 K. The values of lower (Hc1 = 32 Oe) and upper (Hc2 = 335 Oe) critical fields are rather small, confirming that this type II (KG0L = 2.3) weakly coupled (λe-p = 0.5, δCe/γnTc {approximately equal}1.26) 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 spin relaxation analysis 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.
Citation: Physical Review B
Volume: 97
Issue: 1
Pub Type: Journals

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Keywords

Spin-singlet superconductor, spin triplet pairing, noncentrosymmetric crystal structure, Neutron Diffraction, structural transition, specific heat, Magnetization, BCS theory
Created January 04, 2018, Updated June 27, 2018