Probing the superconducting gap symmetry of α − PdBi 2 : A penetration depth study

• Main Authors: Mitra, Sreemanta, Okawa, K., Kunniniyil Sudheesh, S., Sasagawa, T., Zhu, Jian-Xin, Chia, Elbert Ee Min
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2017
• Subjects: Strong-coupling corrections; Superconductor
• Online Access: https://hdl.handle.net/10356/83574; http://hdl.handle.net/10220/43553
• Institution: Nanyang Technological University

We report measurements of the in-plane London penetration depth λ in single crystals of the α−PdBi2 superconductor—the α-phase counterpart of the putative topological superconductor β−PdBi2, down to 0.35 K using a high-resolution tunnel-diode-based technique. Both λ and superfluid density ρs exhibit an exponential behavior for T≤ 0.35Tc, with Δ(0)/kBTc ∼ 2.0, ΔC/γTc ∼ 2.0, and λ(0) ∼ 140 nm, showing that α−PdBi2 is a moderately coupling, fully gapped superconductor. The values of Δ(0) and ΔC/γTc are consistent with each other via strong-coupling corrections.