Superconductivity in 122-type antimonide BaPt2Sb2

Abstract

The crystal structure, superconducting properties, and electronic structure of the novel superconducting 122-type antimonide BaPt2Sb2 have been studied by measurements of powder x-ray diffraction patterns, electrical resistivity, ac magnetic susceptibility, specific heat, and by ab initio calculations. The material crystallizes in a new monoclinic variant of the CaBe2Ge2-type structure, in which Pt2Sb2 layers that consist of PtSb4 tetrahedra, and Sb2Pt2 layers that consist of SbPt4 tetrahedra, are stacked alternatively, with Ba atoms located between them. Measurements of electrical resistivity, ac magnetic susceptibility, and specific heat revealed that BaPt2Sb2 is a superconducting material with a critical temperature of 1.8 K. The electronic heat capacity coefficient and the Debye temperature were 8.62mJ/molK2 and 146(4) K, respectively. The upper critical field and the Ginzburg-Landau coherent length were determined to be 0.27 T and 35 nm, respectively. The calculations showed that the material has two three-dimensional Fermi surfaces (FSs) and two two-dimensional FSs, leading to anisotropic transport properties. The d states of the Pt atoms in the Pt2Sb2 layers are the main contributors to the density of states at the Fermi level. A comparison between experimental and calculated results indicates that BaPt2Sb2 is a superconducting material with moderate coupling.

Source-reported materials — not catalogue approval

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