Speaker
Description
We present unique results of collaborative investigations of Josephson
nanostructures obtained in recent years.We have studied a Josephson junction
involving a Weyl and a multi-Weyl semimetals separated by a barrier created
by putting a gate voltage over the Weyl semimetal.It was shown that the
product of the critical current on the normal-state resistance for such junctions,
has a universal value independent of the barrier potential, which is a consequence
of change in topological winding number across the junction. We have
investigated the perspectives of magnetization control in superconductor /
ferromagnet / superconductor (S/F/S) Josephson junctions on the surface of
a 3D topological insulator hosting Dirac quasiparticles. It was demonstrated
that this can lead to splitting of the ferromagnet’s easy-axis which can lead to
stabilization of an unconventional four-fold degenerate ferromagnetic state.
We have studied a magnetization reversal by an electric current pulse in a
superconductor / insulating ferromagnet / superconductor Josephson junction
placed on top of a 3D topological insulator (TI). It was demonstrated that
strong spin-momentum locking in the TI surface states provides a possibility
of efficient reversal of the magnetic moment by current pulse with amplitude
lower than the critical current, that results in strongly reduced energy dissipation.
We have demonstrated that a current sweep along IV-characteristic of the
S/F/S ?$\phi_0$ junction may lead to regular magnetization dynamics with a series
of specific phase trajectories. It was shown that an external electromagnetic
field allows to control the magnetic moment dynamics and can lead to a
topological transformation of precession trajectories.
