Enhancement of Tc in BiS2 based superconductors NdO0.7F0.3BiS2 by substitution of Pb for Bi

TL;DR

This study demonstrates that substituting Pb for Bi in NdO0.7F0.3BiS2 enhances its superconducting transition temperature, reaching a maximum of 5.6 K, with lattice strain playing a key role.

Contribution

It is the first to show that Pb substitution increases Tc in NdO0.7F0.3BiS2 under ambient pressure conditions.

Findings

Tc increases with Pb substitution up to 6%

Maximum Tc achieved is 5.6 K

Pb substitution causes lattice shrinkage along the c axis

Abstract

We succeed in enhancement of a superconducting transition temperature (Tc) for NdO0.7F0.3BiS2 single crystal by partial substitution of Pb for Bi. The Tc increases with increasing Pb concentration until 6%. The maximum Tczero is 5.6 K, which is the highest value among BiS2 based superconductors synthesized under an ambient pressure. Pb substitution for Bi induces lattice shrinkage along the c axis. These results reflect that superconductivity in this system is responsive to the lattice strain.