Flux growth, mixed valence state and superconductivity of Sn4Sb3 intermetallic crystals. (October 2021)

• Record Type: Journal Article
• Authors: Liu, Bin; Zhu, Xiaowei; Xiao, Guorui; Liu, Yi; Wu, Jifeng; Cui, Yanwei; Zhu, Qinqing; Wu, Siqi; Lu, Xin; Cao, Guang-han; Ren, Zhi
• Is Part Of: Intermetallics. Volume 137(2021)
• Publication Date: 2021-10
• Subjects: Sn–Sb intermetallic Compound -- Crystal growth -- Mixed valence state -- Superconductivity -- Density of states; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2021.107301
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: Single crystals of Sn4 Sb3 with mm size have been obtained for the first time via a Sn flux method. Structural refinements confirm its trigonal structure with the centrosymmetric R 3 ̄ m space group. The unit cell consists of ordered [Sn–Sb–Sn–Sb–Sn–Sb–Sn] lamellae stacked along the c -axis, in which Sn is found to exhibit mixed valence states of 0 and 2+. Below 1.47 K, single crystalline Sn4 Sb3 becomes a weakly coupled, fully gapped superconductor. In contrast to polycrystalline samples, the resistive transition of Sn4 Sb3 crystals coincides well with the specific-heat jump, which supports that grain boundaries are responsible for the higher resistive T c in the former case. Theoretical calculations show that the density of states at the Fermi level are mainly contributed by Sn and Sb 5 p orbitals and almost unaffected by the spin-orbit interaction. Our study lays a foundation for experimental investigations of the predicted topological properties in this intermetallic compound. Highlights: Sn4 Sb3 crystals with mm size are grown by a Sn flux method. The structure consists of [Sn4 Sb3 ] lamellae stacked along the c-axis. Sn exhibits mixed valence states of 0 and 2+. The crystals exhibit BCS-like superconductivity below 1.47 K. The density of states at the Fermi level are dominated by Sn and Sb 5 p orbitals.