Scanning tunneling microscopy study of superconductivity, magnetic vortices, and possible charge-density wave in Ta4Pd3Te16

Ta4Pd3Te16 is a newly discovered layered superconductor with quasi-one-dimensional (1D) structure. Recent thermal transport measurements show the possible existence of nodes in the superconducting gap. Here we report low-temperature scanning tunneling microscopy/ spectroscopy study on Ta4Pd3Te16 single crystals. We observed stripelike structure composed of atom chains on the cleaved ((1) over bar 03) surface. There exists charge-density-wave (CDW)- like modulations along stripes with commensurate periods. Meanwhile, the tunneling conductance shows an s-wave-like superconducting gap. The magnetic vortex mapped at low field is highly anisotropic with a bound state in the core. At increased field, strong vortex overlapping is directly observed and the bound state is suppressed, indicating the delocalization of the superconducting quasiparticles. Our observations suggest that Ta4Pd3Te16 is of multiband superconductivity with strong 1D characters, which possibly coexist with CDW transition.