Exotic superconducting behavior in layer engineered BCS superconductor
Abstract
Rich in exotic properties, recent excitements in the field of superconductivity are related to topological superconductors, spin triplet pairing and nonreciprocal supercurrent flow. A superconducting (SC) strip is not expected to show polarity dependence of the critical current (Ic). However, a superconductor exhibiting nonreciprocal (polarity dependent) Ic is of fundamental and technological interest; could lead to perfect dissipationless (resistive) transmission along one (opposite) direction, an ideal SC diode rectification. Theoretical prediction is that breaking of the time-reversal and inversion symmetries in a superconductor with Rashba spin-orbit coupling and Zeeman field supports a helical SC phase, creating a non-centrosymmetric superconductor. We have most recently observed that the SC diode effect is ubiquitous. With out-of-plane magnetic field, a sensitive SC diode effect even with 1 Oe field is seen in V and Nb thin films, attributed to strip edge asymmetry. Remarkably large nonreciprocal Ic reaching a giant diode efficiency of 65percent (highest yet) is realized by coupling V with ferromagnetic insulator EuS layer, which persists even at zero field, showing nonvolatile diode rectification. Meissner screening current in the superconductor defines the nonreciprocity of Ic, besides the dependence on EuS magnetic domain features.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 22, 2024
- Source ID
- FA95502310004
Entities
People
- Jagadeesh Moodera
Organizations
- Air Force Office of Scientific Research
- Massachusetts Institute of Technology
- United States Air Force