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

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 ($P{6}_3/mmc$, $D_{6h}^4$, 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 ($P{2}_{1}3$, $T^4$, 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.

8 pages, 7 figures, 2 tables