2010 Volume 79 Issue 1 Pages 43-47
We introduce new superconducting phenomena and functions of multiband superconductors, such as multilayer cuprate superconductors, and discuss their possible applications to electronics. Each band is considered to have its own superconducting phase when the interband interaction is much smaller than the intraband interaction. Leggett (1966) proposed that the interband phase difference plays an important role in such superconductors. We theoretically discovered the interband phase difference soliton in 2001. This soliton is the origin of other rich topologies, such as a fractional quantization of the magnetic flux, a quantum phase domain, a fractional vortex, and a vortex molecule. These topologies result in a new quantum dynamics as well as a new superconducting electronics.
