Possibility for conventional superconductivity in Sr_0.1Bi₂Se₃ from high-pressure transport studies

Sr_xBi₂Se₃ is recently reported to be a superconductor derived from topological insulator Bi₂Se₃. It shows a maximum resistive T _c of 3.25 K at ambient pressure. We report magnetic (up to 1 GPa) and transport properties (up to 8 Gpa) under pressure for single crystalline Sr_0.1Bi₂Se₃ superconductor. Magnetic measurements show that T _c decreases from ∼2.6 K (0 GPa) to ∼1.9 K (0.81 GPa). Similar behavior is observed in transport properties as well without much change in the metallic characteristics in normal-state resistivity. No reentrant superconducting phase (Zhou Y. et al., Phys. Rev. B, 93 (2016) 144514) is observed at high pressure. Normal-state resistivity near T _c is explained by Fermi liquid model. Band structure calculations indicate decreasing density of states at Fermi level with pressure. In consonance with transition temperature suppression in conventional BCS low-T _c superconductors, the pressure effect in Sr_xBi₂Se₃ is well accounted by pressure-induced band broadening.