Nano-bridge Josephson junction has been fabricated with Fe0.94Te0.45Se0.55 (FTS) thin films by using focused ion beam etching (FIB). Electrical properties of the Josephson effects of the nano-bridge have been deeply studied. Current-voltage (I-V) characteristics of the junction exhibit resistively and capacitively shunted junction-like (RCSJ) behaviors. Critical current of the junction is 16.1 mA at 4.2 K. The product of the critical current and normal state resistance (IcRn) is higher than those reported in the literatures. Thermal conductance of the nano-bridge increases with increasing resistance, which suggests that the thermal transfer has been enhanced. Noise equivalent power of the nano-bridge is at the order of magnitude of 10-12 WHz-1/2, which is comparable to that of the NbN bolometer. With these unique electrical characteristics, the FTS based nano-bridge could have various potential applications.

Graphical Abstract

Fabrication and characterization of nano-bridge Josephson junction based on Fe0.94Te0.45Se0.55 thin film