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

¹Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 3^rd South Street, Zhongguancun, Beijing, 100190, China

²Purple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, No.2 West Beijing Road, Nanjing, Jiangsu, 210008, People’s Republic of China

³Department of Physics, Southern University of Science and Technology (SUSTech), No. 1088 Xueyuan Road, Shenzhen, Guangdong, 518055, China

⁴CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, 3^rd South Street, Zhongguancun, Beijing, 100190, China

Adv. Mater. Lett., 2019, 10 (5), pp 319-323

DOI: 10.5185/amlett.2019.2270

Publication Date (Web): Jan 14, 2019

Copyright © IAAM-VBRI Press

E-mail: lyan@iphy.ac.cn

Abstract

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.

Keywords

Nano-bridge Josephson junction, iron-based superconductor.