Discovery of superconductivity in Nb4SiSb2 with a V4SiSb2-type structure and implications of interstitial doping on its physical properties. Issue 32 (29th July 2022)

• Record Type: Journal Article
• Authors: Balestra, Manuele D.; Atanov, Omargeldi; Lefèvre, Robin; Blacque, Olivier; Ng, Yat Hei; Lortz, Rolf; von Rohr, Fabian O.
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 32(2022)
• Page Start: 11703
• Page End: 11709
• Publication Date: 2022-07-29
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2tc01510b
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : We report on the discovery of Nb4 SiSb2 . This compound is a new superconductor with a T c of 1.6 K. The channel void positions of this phase can be partly filled with Cu, Pd, or Pt, which leads to a lowering of the transition temperature. Abstract : We report on the discovery, structural analysis, and the physical properties of Nb4 SiSb2 – a hitherto unknown compound crystallizing in the V4 SiSb2 -type structure with the tetragonal space group I 4/ mcm and unit cell parameters a = 10.3638(2) Å and c = 4.9151(2) Å. We find Nb4 SiSb2 to be a metal undergoing a transition to a superconducting state at a critical temperature of T c ≈ 1.6 K. The bulk nature of the superconductivity in this material is confirmed by the observation of a well defined discontinuity in specific heat with a normalized specific heat jump of Δ C ( T c )/ γT c = 1.33 mJ mol −1 K −2 . We find that for Nb4 SiSb2, the unoccupied sites on the 4b Wyckoff position can be partially occupied with Cu, Pd, or Pt. Low-temperature resistivity measurements show transitions to superconductivity for all three compounds at T c ≈ 1.2 K for Nb4 Cu0.2 SiSb2, and T c ≈ 0.8 K for Nb4 Pd0.2 SiSb2 as well as for Nb4 Pt0.14 SiSb2 . The addition of electron-donor atoms into these void positions, henceforth, lowers the superconducting transition temperature in comparison to the parent compound.