Superconducting density of states of PtPb4

Abstract

PtPb${}_4$ is a type II superconductor with a bulk critical temperature $T_c\approx 3$K and an upper critical field of $H_{c2}=0.36$T. PtPb${}_4$ is related to non-superconducting PtSn${}_4$, which presents nodal arc states at the surface. Here we measure the superconducting density of states of PtPb${}_4$ using millikelvin Scanning Tunneling Microscopy (STM). We observe a fully opened superconducting gap of $\Delta =0.48$\ meV similar to expectations from Bardeen Cooper and Schrieffer (BCS) theory (${\Delta }_0=1.76k_B{T}_c=0.49$meV). Measurements under magnetic fields applied perpendicular to the surface show a spatially inhomogeneous gap structure, presenting superconducting signatures at fields as high as 1.5 T, significantly above $H_{c2}=0.36$T. On some locations we find that the superconducting density of states does not vanish above $T_c$. We can find signatures of a superconducting gap up to 5K. We discuss possible reasons for the observation of superconducting properties above $T_c$ and $H_{c2}$, emphasizing the role played by structural defects.

References in corpus (13)

• Titanic Magnetoresistance in WTe2
• Superconducting density of states and vortex cores of 2H-NbS2
• Superconducting Arcs
• Surface superconductivity in the topological Weyl semimetal t-PtBi${}_2$
• Nonsymmorphic Symmetry-Protected Band Crossings in a Square-Net Metal PtPb${}_4$
• Millikelvin scanning tunneling microscope at 20/22 T with a graphite enabled stick-slip approach and an energy resolution below 8$\mu$eV: Application to conductance quantization at 20 T in single atom point contacts of Al and Au
• Quantum-well states at the surface of the heavy-fermion superconductor URu${}_2$Si${}_2$
• Simplified feedback control system for Scanning Tunneling Microscopy
• Probing the topological surface states in superconducting Sn4Au single crystal: A magneto transport study
• Superconductivity in PtPb${}_4$ with Possible Nontrivial Band Topology
• Band structure, superconductivity and polytypism in AuSn${}_4$
• Superconducting density of states and bandstructure at the surface of the candidate topological superconductor Au2Pb
• Methods to simplify cooling of liquid Helium cryostats

Cited by in corpus (1)

• Scanning tunneling spectroscopy of superconducting nitridized aluminum thin films