Electronic spin polarization in the Majorana bound state in one-dimensional wires

We have studied the effect of magnetic field and disorder on the electronic z-spin polarization at the ends of the one-dimensional wire with strong Rashba spin–orbit coupling deposited on an s-wave superconductor. It was shown that in the topologically nontrivial phase the polarization as well as the energy of the Majorana bound state oscillate as a function of the magnetic field. Despite being substantially nonzero in the low transversal and longitudinal fields the polarization at one of the wire's ends is significantly suppressed at a certain range of the magnitudes and angles of the canted magnetic field. Thus, in this case the polarization cannot be regarded as a local order parameter. However, the sum of the absolute values of the polarization at both ends remains significantly nonzero. It was demonstrated that Anderson disorder does not seriously affect observed properties but leads to the appearance of the additional areas with weak spin polarization at the high magnetic fields.