Structural and superconducting analysis of topologically non-trivial alloy of Sn1-xSbx (x=0.4, 0.5, 0.6)

Abstract

In the present article, we report a comprehensive study of structural and physical properties of binary alloy Sn1-xSbx (x = 0.4, 0.5, 0.6). All the alloys are grown through the self-flux method under well-optimized heat treatment. The as-grown crystals are structurally characterized through Powder X-Ray Diffraction (PXRD), Scanning Electron Microscope (SEM), and Energy Dispersive X-Ray Analysis (EDAX). Simultaneously, the X-Ray Photoelectron Spectroscopy (XPS) is used to probe the surface of the crystals. All the crystals crystallize in rhombohedral structure with the R −3 m space group, as confirmed from Rietveld refined PXRD pattern. Sn1-xSbx is found to have a secondary phase with an elongated unit cell in conjunction with the primary phase for a specific alloy of x = 0.6. These binary systems are considered to be a possible candidate of topological superconductivity as they show the opening of bands near Fermi level with the inclusion of Spin-Orbit Coupling (SOC) protocols in DFT calculations. However, the superconductivity in all samples is confirmed through DC magnetization measurements under Field Cooled (FC) and Zero Field Cooled (ZFC) measurement at 10 Oe magnetic field. The nature of observed superconductivity is determined by isothermal magnetization (M-H) measurements at 2K, in which these binary alloys are proved to be type-II superconductors.