Bound states and controllable currents on topological insulator surfaces with extended magnetic defects

Controlling the spin current around the rectangular cavities in two-dimensional topological insulators

“…The two types of magnetic defects, including Ising symmetry ( J z S a 0 and J AE S = 0) and xy symmetry ( J z S = 0 and J AE S a 0), enable different patterns of spin-polarized currents. 46,52,53 The formalism of bond current allows for the computation of physically measurable spatial profiles of local current within the TIs in the non-equilibrium condition. The spin-resolved bond current is calculated using the equations-of-motion approach for nonequilibrium Green's functions 54…”

“…Assuming that the magnetic defects are static in nature, the scattering of the TI's conduction electrons by magnetic defects at R is described by the Hamiltonian 52 where the sum runs over all defect locations. The two types of magnetic defects, including Ising symmetry ( J z S ≠ 0 and J ± S = 0) and xy symmetry ( J z S = 0 and J ± S ≠ 0), enable different patterns of spin-polarized currents.…”

“…The two types of magnetic defects, including Ising symmetry ( J z S ≠ 0 and J ± S = 0) and xy symmetry ( J z S = 0 and J ± S ≠ 0), enable different patterns of spin-polarized currents. 46,52,53…”