Anisotropic Superconducting Gap and Elongated Vortices with Caroli-De-Gennes-Matricon States in the New Superconductor Ta4Pd3Te16

TL;DR

This study uses scanning tunneling microscopy to reveal anisotropic superconducting gaps, elongated vortices, and Caroli-de-Gennes-Matricon states in the new superconductor Ta4Pd3Te16, highlighting its unique electronic and vortex properties.

Contribution

It reports the first observation of elongated vortices and anisotropic superconducting gaps in Ta4Pd3Te16, a newly discovered superconductor, linking electronic anisotropy to vortex shape.

Findings

Elongated vortices with anisotropy ratio ~2.5 observed.

Evidence of anisotropic superconducting gap with possible nodes.

Clear Caroli-de-Gennes-Matricon states within vortex cores.

Abstract

The superconducting state is formed by the condensation of a large number of Cooper pairs. The normal state electronic properties can give significant influence on the superconducting state. For usual type-II superconductors, the vortices are cylinder like with a round cross-section. For many two dimensional superconductors, such as Cuprates, 2H-NbSe$_2$ etc., albeit the in-plane anisotropy, the vortices generally have a round shape. In this paper we report results based on the scanning tunneling microscopy/spectroscopy measurements on a newly discovered superconductor Ta$_4$Pd$_3$Te$_{16}$. The chain like conducting channels of PdTe$_2$ in Ta$_4$Pd$_3$Te$_{16}$ make a significant anisotropy of the in-plane Fermi velocity. We suggest at least one anisotropic superconducting gap with gap minima or possible node exists in this multiband system. In addition, elongated vortices are observed with an anisotropy of $\xi_{\parallel b}/\xi_{\perp b}\approx 2.5$. Clear Caroli-de-Gennes-Matricon states are also observed within the vortex cores. Our results will initiate the study on the elongated vortices and superconducting mechanism in the new superconductor Ta$_4$Pd$_3$Te$_{16}$.