Flip-flopping fractional flux quanta.
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.
Ortlepp
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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
Ariando
Mielke
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Verwijs
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CJ
Foo
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Rogalla
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Uhlmann
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Hilgenkamp
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