Multiband superconductivity in Ta$_4$Pd$_3$Te$_{16}$ with anisotropic gap structure

TL;DR

This study provides evidence of multiband superconductivity with an anisotropic gap structure in Ta$_4$Pd$_3$Te$_{16}$, characterized by anisotropic critical fields and a two-gap $s$+$d$ wave model fitting specific heat data.

Contribution

First comprehensive experimental evidence of multiband superconductivity with anisotropic gaps in Ta$_4$Pd$_3$Te$_{16}$ using magnetoresistance, susceptibility, and specific heat measurements.

Findings

Ta$_4$Pd$_3$Te$_{16}$ is an anisotropic type-II superconductor.

The upper critical field $H_{c2}$ shows a linear temperature dependence at low T.

Electronic specific heat fits a two-gap ($s$+$d$ waves) model.

Abstract

We carried out the measurements of magnetoresistance, magnetic susceptibility and specific heat on crystals of the low-dimensional transition metal telluride Ta$_4$Pd$_3$Te$_{16}$. Our results indicate that Ta$_4$Pd$_3$Te$_{16}$ is an anisotropic type-II superconductor with the extracted Ginzburg-Landau parameter $\kappa_{\text{GL}}=$ 84. The upper critical field $H_{c2}$($T$) shows a linear dependence at low temperature and the anisotropy of $H_{c2}$($T$) is strongly $T$-dependent, both of which indicate a multiband scenario. A detailed analysis reveals that the electronic specific heat $C_{\text{el}}$($T$) can be consistently described by a two-gap ($s$+$d$ waves) model from the base temperature $T/T_c\sim$ 0.12 up to $T_c$. Our data suggests multiband superconductivity in Ta$_4$Pd$_3$Te$_{16}$ with anisotropic gap structure.