Superconductivity at 2.5 K in new transition-metal chalcogenide Ta2PdSe5

TL;DR

This paper reports the discovery of a new transition-metal chalcogenide, Ta$_2$PdSe$_5$, which exhibits bulk superconductivity at 2.5 K, with evidence of multi-band behavior from specific heat and critical field measurements.

Contribution

The study introduces a new superconductor Ta$_2$PdSe$_5$ with unique multi-band superconducting properties and high upper critical field exceeding theoretical limits.

Findings

Superconducting transition temperature $T_c$ is approximately 2.5 K.

Evidence of two-gap BCS superconductivity from specific heat data.

Upper critical field $H_{c2}$ exceeds Pauli and orbital limiting fields.

Abstract

We report the synthesis and superconducting properties of a new transition-metal chalcogenide Ta$_2$PdSe$_5$. The measurements of resistivity, magnetization, and specific heat reveal that Ta$_2$PdSe$_5$ is a bulk superconductor with $T_c$ $\simeq$ 2.5 K. The zero-field electronic specific heat in the superconducting state can be fitted with a two-gap BCS model. The upper critical field $H_{c2}$ shows a linear temperature dependence, and the value of $H_{c2}$(0) is much higher than the estimated Pauli limiting field $H_{c2}^{P}$ and orbital limiting field $H_{c2}^{orb}$. All these results of specific heat and upper critical field suggest that Ta$_2$PdSe$_5$ is a multi-band superconductor.