Synthesis, characterization, and electronic structure of SrBi2S4

Abstract

Black-colored crystals and a pure polycrystalline phase of SrBi2S4 were synthesized using the high-temperature sealed tube method. A single-crystal and powder X-ray diffraction studies established the crystal structure and phase purity of SrBi2S4, respectively. It crystallizes in the hexagonal C6h2 −P63/m (176) space group with lattice parameters of a ​= ​b ​= ​24.9335(6) Å and c ​= ​4.0946(1) Å. The structure is made up of three-dimensional 3∞ [Bi2S4]4− anionic framework with one-dimensional tunnels which are occupied by Sr atoms. The optical bandgap and temperature-dependent resistivity studies indicated semiconducting nature for polycrystalline SrBi2S4 in agreement with the theoretical DFT study. The thermal conductivity (κ) of a cold-pressed sintered disk of SrBi2S4 decreases on heating the sample. The κ values vary from ∼0.65 ​W/mK at 300 ​K to ∼0.55 ​W/mK at 773 ​K. The COHP analysis is performed to estimate the relative strength of chemical bonding between Bi–S and Sr–S pairs. © 2022 Elsevier Inc