FeTe(0.55)Se(0.45) van der Waals tunneling devices

  Ayelet Zalic  ,  Shahar Simon  ,  Sergei Remennik  ,  Atzmon Vakahi  ,  Genda D. Gu  ,  Hadar Steinberg  
Racah Institute of Physics, Hebrew University of Jerusalem
Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem
Brookhaven National Laboratory, Condensed Matter Physics and Material Science Department

FeTe(0.55)Se(0.45) is an unconventional superconductor gaining attention recently for its low Fermi energy, which is not much larger than the superconducting gap. This enables the observation of interesting phenomena such as the BCS-BEC crossover and discrete vortex bound states. Moreover, possible signatures of a topological superconducting surface state have been observed. We have succeeded in integrating this material into heterostructures with 2D layered materials. Further developement of fabrication techniques is necessary, and if successful could lead to a wide range of possibilities to probe the physics of the material using transport and tunneling measurements. I will present the fabrication techniques we use, and discuss the challenges involved in working with this material, which we attribute to surface degradation. I will also present data of hard-gap tunneling and defect assisted tunneling into the material.