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arXiv · 1207.3013

Experimental evidence of a ϕ Josephson junction

H. Sickinger·A. Lipman·M. Weides·R. G. Mints·H. Kohlstedt·D. Koelle·R. Kleiner·E. Goldobin
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Abstract

We demonstrate experimentally the existence of Josephson junctions having a doubly degenerate ground state with an average Josephson phase ψ=\pmϕ. The value of ϕ can be chosen by design in the interval 0<ϕ<π. The junctions used in our experiments are fabricated as 0-π Josephson junctions of moderate normalized length with asymmetric 0 and π regions. We show that (a) these ϕ Josephson junctions have two critical currents, corresponding to the escape of the phase ψ from -ϕ and +ϕ states; (b) the phase ψ can be set to a particular state by tuning an external magnetic field or (c) by using a proper bias current sweep sequence. The experimental observations are in agreement with previous theoretical predictions.

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H. Sickinger, A. Lipman, M. Weides, R. G. Mints, H. Kohlstedt, D. Koelle, R. Kleiner, E. Goldobin. 2012-07-12. Experimental evidence of a ϕ Josephson junction. https://doi.org/10.1103/physrevlett.109.107002

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