Title: Electrically controllable spin filtering based on superconducting helical states,
Abstract: The magnetoelectric effects in the surface states of the 3D TI are extremely
strong due to the full spin-momentum locking. Here the microscopic theory of
S/3D TI bilayer structures in terms of quasiclassical Green's functions is
developed. On the basis of the developed formalism it is shown that the DOS in
the S/TI bilayer manifests giant magnetoelectric behavior and, as a result,
S/3D TI heterostructures can work as non-magnetic fully electrically
controllable spin filters. It is shown that due to the full spin-momentum
locking the amplitudes of the odd-frequency singlet and triplet components of
the consensate wave function are equal. The same is valid for the even
frequency singlet and triplet components. We unveil the connection between the
odd-frequency pairing in S/3D TI heterostructures and magnetoelectric effects
in the DOS.