Manipulation of quasi-1D states bound to a line defect on topological insulator surface

We consider a line defect on the surface of a topological insulator (TI). It is known that purely potential scattering on such a defect results in quasi-1D bound states, and we clarify the origin of these states. We further include magnetic scattering at the line defect (for example, due to localized moments). We show that magnetic scattering, by itself or in combination with potential scattering,  allows for quasi-1D bound states to form. The dispersion and spin structure of these states depend on the relative strengths of magnetic and potential scattering, and the direction of localized moments at the defect. This potentially allows for the manipulation of these states using a magnetic field. We also discuss the spin textures and currents generated by these states, and their role in proximity-induced superconductivity.