Superconductivity at 10.4 K in a novel quasi-one-dimensional ternary molybdenum pnictide K2Mo3As3

TL;DR

This paper reports the discovery of a new quasi-one-dimensional molybdenum pnictide superconductor, K2Mo3As3, with a transition temperature of 10.4 K, expanding the family of related superconducting materials.

Contribution

The study introduces the first ternary molybdenum pnictide superconductor K2Mo3As3 with a unique quasi-one-dimensional structure and higher Tc than similar Cr-based compounds.

Findings

Superconductivity observed at 10.4 K in K2Mo3As3.

Crystalline structure is quasi-one-dimensional with hexagonal symmetry.

Bulk superconductivity confirmed through resistivity, susceptibility, and heat capacity measurements.

Abstract

Here we report the discovery of the first ternary molybdenum pnictide based superconductor K2Mo3As3. Polycrystalline samples were synthesized by the conventional solid state reaction method. X-ray diffraction analysis reveals a quasi-one-dimensional hexagonal crystal structure with (Mo3As3)2- linear chains separated by K+ ions, similar as previously reported K2Cr3As3, with the space group of P-6m2 (No. 187) and the refined lattice parameters a = 10.145(5) {\AA} and c = 4.453(8) {\AA}. Electrical resistivity, magnetic susceptibility, and heat capacity measurements exhibit bulk superconductivity with the onset Tc at 10.4 K in K2Mo3As3 which is higher than the isostructural Cr-based superconductors. Being the same group VIB transition elements and with similar structural motifs, these Cr and Mo based superconductors may share some common underlying origins for the occurrence of superconductivity and need more investigations to uncover the electron pairing within a quasi-one-dimensional chain structure.