title: Flip-flopping fractional flux quanta.
abstract: The d-wave pairing symmetry in high-critical temperature superconductors makes it possible to realize superconducting rings with built-in pi phase shifts. Such rings have a twofold degenerate ground state that is characterized by the spontaneous generation of fractional magnetic flux quanta with either up or down polarity. We have incorporated pi phase-biased superconducting rings in a logic circuit, a flip-flop, in which the fractional flux polarity is controllably toggled by applying single flux quantum pulses at the input channel. The integration of p rings into conventional rapid single flux quantum logic as natural two-state devices should alleviate the need for bias current lines, improve device symmetry, and enhance the operation margins.
authors.affiliation: Institute of Information Technology, Rapid Single-Flux Quantum (RSFQ) Design Group, University of Technology Ilmenau, Post Office Box 100565, D-98684 Ilmenau, Germany. thomas.ortlepp@tu-ilmenau.de
authors.forename: T
authors.initials: T
authors.lastname: Ortlepp
authors.lastname: Ariando
authors.forename: O
authors.initials: O
authors.lastname: Mielke
authors.forename: C J M
authors.initials: CJ
authors.lastname: Verwijs
authors.forename: K F K
authors.initials: KF
authors.lastname: Foo
authors.forename: H
authors.initials: H
authors.lastname: Rogalla
authors.forename: F H
authors.initials: FH
authors.lastname: Uhlmann
authors.forename: H
authors.initials: H
authors.lastname: Hilgenkamp