134 research outputs found
Josephson effect through magnetic skyrmion
We discover that the multiple degrees of freedom associated with magnetic
skyrmions: size, position, and chirality, can all be used to control the
Josephson effect and 0-pi transitions occurring in superconductor/magnetic
skyrmion/superconductor junctions. In the presence of two skyrmions, the
Josephson effect depends strongly on their relative chirality and leads to the
possibility of a chirality-transistor effect for the supercurrent where the
critical current is changed by several orders of magnitude simply by reversing
the chirality of a magnetic skyrmion. Moreover, we demonstrate that the
Fraunhofer pattern can show a local minimum at zero flux as a direct result of
the skyrmion magnetic texture. These findings demonstrate the rich physics that
emerges when combining topological magnetic objects with superconductors and
could lead to new perspectives in superconducting spintronics.Comment: 5 pages, 5 figure
Superconducting Proximity Effect in Silicene: Spin-Valley Polarized Andreev Reflection, Non-Local Transport, and Supercurrent
We theoretically study the superconducting proximity effect in silicene,
which features massive Dirac fermions with a tunable mass (band gap), and
compute the conductance across a normal/superconductor (N/S) silicene junction,
the non-local conductance of an N/S/N junction, and the supercurrent flowing in
an S/N/S junction. It is demonstrated that the transport processes consisting
of local and non-local Andreev reflection may be efficiently controlled via an
external electric field owing to the buckled structure of silicene. In
particular, we demonstrate that it is possible to obtain a fully spin-valley
polarized crossed Andreev reflection process without any contamination of
elastic cotunneling or local Andreev reflection, in stark contrast to ordinary
metals. It is also shown that the supercurrent flowing in the S/N/S junction
can be fully spin-valley polarized and that it is controllable by an external
electric field.Comment: 5 pages, 4 figures + supplementary informatio
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