C-axis electrical resistivity of PrO$_{1-a}$F$_a$BiS$_2$ single crystals

TL;DR

This study investigates the c-axis electrical resistivity of PrO$_{1-a}$F$_a$BiS$_2$ single crystals, demonstrating their high anisotropy and potential as intrinsic Josephson junctions through experimental growth, characterization, and magnetic field measurements.

Contribution

The paper reports the successful growth and detailed c-axis transport characterization of PrO$_{1-a}$F$_a$BiS$_2$ single crystals, highlighting their high anisotropy and Josephson vortex behavior.

Findings

High anisotropy (~40-50) estimated from effective mass model.

Zero resistivity at 2.7 K along the c-axis.

Observation of hysteresis in the current-voltage curve and a lock-in state under magnetic field.

Abstract

The high anisotropy in RO1-aFaBiS2 (R denotes a rare-earth element) superconductors demonstrates their potential use as intrinsic Josephson junctions, considering the weak coupling among BiS2-PrO(F)-BiS2 (superconducting-normal-superconducting) layers along the c-axis. We grew PrO1-aFaBiS2 single crystals using CsCl/KCl flux. The superconducting anisotropies of the grown single crystals were estimated to be approximately 40-50 from the effective mass model. The c-axis transport properties were characterized using single-crystal s-shaped intrinsic Josephson junctions with a focused ion beam. Along the c-axis, the crystals showed zero resistivity at 2.7 K and a critical current density of 1.33*10^3 A/cm2 at 2.0 K. The current-voltage curve along the c-axis displayed hysteresis. The c-axis transport measurements under a magnetic field parallel to the ab-plane revealed a "lock-in" state due to the Josephson vortex flow, indicating that BiS2 superconductors are promising candidates for intrinsic Josephson junctions.