Evidence for conventional superconductivity in Sr0.1Bi2Se3 from high pressure studies

TL;DR

This study investigates how applying pressure affects the superconducting transition temperature and electronic properties of Sr0.1Bi2Se3, revealing pressure-induced band broadening consistent with conventional BCS superconductivity.

Contribution

It provides the first detailed pressure-dependent magnetic and transport measurements for Sr0.1Bi2Se3, demonstrating suppression of Tc and band structure changes under pressure.

Findings

Tc decreases from 2.6 K to 1.9 K under pressure.

Normal state resistivity remains metallic with no reentrant phase.

Band structure calculations show decreasing density of states at Fermi level.

Abstract

SrxBi2Se3 is recently reported to be a superconductor derived from topological insulator Bi2Se3. It shows a maximum resistive Tc of 3.25 K at ambient pressure. We report magnetic (upto 1 GPa) and transport properties (upro 8 Gpa) under pressure for single crystalline Sr0.1Bi2Se3 superconductor. Magnetic measurements show that Tc 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 (Physical Review B 93, 144514 (2016)) is observed at high pressure. Normal state resistivity near Tc is explained by Fermi liquid model. Above 100 K, a polaronic hopping conduction mechanism with two parallel channels for current flow is indicated. Band structure calculations indicate decreasing density of states at Fermi level with pressure. In consonance with transition temperature suppression in conventional BCS low Tc superconductors, the pressure effect in SrxBi2Se3 is well accounted by pressure induced band broadening.