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Fully gapped superconductivity in the topological superconductor beta-PdBi2

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Biswas Pabitra et al.,
Project Superconductivity in Unconventional Metals and its Interplay with Magnetism
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Original article (peer-reviewed)

Volume (Issue) 93(22)
Page(s) 220504
Title of proceedings PHYSICAL REVIEW B
DOI 10.1103/physrevb.93.220504


The recent discovery of the topologically protected surface states in the beta phase of PdBi2 has reignited the research interest in this class of superconductors. Here, we show results of our muon spin relaxation and rotation (mu SR) measurements carried out to investigate the superconducting and magnetic properties and the topological effect in the superconducting ground state of beta-PdBi2. Zero-field mu SR data reveal that no sizable spontaneous magnetization arises with the onset of superconductivity implying that the time reversal symmetry is preserved in the superconducting state of beta-PdBi2. Further, a strong diamagnetic shift of the applied field has been observed in the transverse-field (TF) mu SR experiments, indicating that any triplet-pairing channel, if present, does not dominate the superconducting condensate. Using TF-mu SR, we estimate that the magnetic penetration depth. lambda = 263(10) nm at zero temperature. The nature of lambda(T) provides evidence for the existence of a nodeless single s-wave type isotropic energy gap of 0.78(1) meV at zero temperature. Our results further suggest that the topologically protected surface states have no effect on the bulk of the superconductor.