Group seminar Theoretical Physics II

14.11.2018 10 a.m., room: T-2003
Dr. Grigory Tkachov (Theoretische Physik II)
Topological Matter: Concepts and Models
18.1.2019 2 p.m., room: S-439
Jakob Bonart (Theoretische Physik III)
NRG - A real frequency impurity solver (I)
25.1.2019 2 p.m., room: S-439
Jakob Bonart (Theoretische Physik III)
NRG - A real frequency impurity solver (II)
7.2.2019 2 p.m., room: R-506
Andreas Weh (Theoretische Physik II & III)
Transport in correlated heterostructures
22.3.2019 2 p.m., room: S-288
Dr. F. Sebastián Bergeret (Materials Physics Center, CSIC, Spain)
Universal correspondence between edge spin accumulation and equilibrium spin-currents in nanowires

Although equilibrium spin currents (ESC) may exist in materials with spin-orbit coupling, they are not transport currents and cannot lead to spin accumulation in the presence of time-reversal symmetry. It is for this reason that the detection of ESC has remained elusive. Here we show that in a nanowire with spin-orbit coupling, a Zeeman field leads to a bulk equilibrium spin current that flows along the wire and manifests itself in a sizable edge spin polarization, transverse to the Zeeman field. The net accumulated spin does not depend on specific properties of the wire ends, being fully determined by the bulk spin current. This bulk-boundary correspondence is a universal property that occurs in both, the normal and superconducting state, independently of the degree of disorder. The transverse edge spin polarization is strongly enhanced in the superconducting state when the Zeeman energy is of the order of the induced superconducting gap. This leads to a hitherto unknown transverse magnetic susceptibility that can be much larger than the longitudinal one and it drastically changes the paramagnetic response of the nanowire.