Superconductivity in Hexagonal BaPtAs: SrPtSb- and YPtAs-type Structures with Ordered Honeycomb Network

TL;DR

This study reports the discovery of superconductivity in two hexagonal BaPtAs structures with different honeycomb stacking sequences, highlighting the relationship between crystal structure and superconducting properties.

Contribution

It identifies and characterizes two new hexagonal BaPtAs structures with distinct stacking sequences that exhibit superconductivity, expanding understanding of structure-property relationships.

Findings

Superconductivity at 2.8 K in SrPtSb-type structure.

Superconductivity at 2.1-3.0 K in YPtAs-type structure.

Cubic LaIrSi-type structure does not superconduct above 0.1 K.

Abstract

The crystal structure and superconductivity of hexagonal BaPtAs are reported. Single-crystal X-ray diffraction, magnetization, electrical resistivity, and specific heat measurements were performed in this study. Two hexagonal structures with different PtAs honeycomb network stacking sequences, namely, SrPtSb- (space group $P\bar{6}m2$, $D_{3h}^1$, No. 187) and YPtAs-type ($P6_3/mmc$, $D_{6h}^4$, No. 194) structures, were identified and found to exhibit superconductivity at 2.8 and 2.1-3.0 K, respectively. In contrast, the cubic LaIrSi-type structure ($P2_13$, $T^4$, No. 198) did not exhibit superconductivity above 0.1 K. BaPtAs provides a unique opportunity to study superconductivity with broken and preserved spatial inversion symmetry.