Solitonic Dirac fermion wave guide networks on topological insulator surfaces

摘要

Magnetic texturing on the surface of a topological insulator allows the design of wave guide networks and beam splitters for domain-wall Dirac fermions. Guided by simple analytic arguments, we model a Dirac domain-wall fermion interferometer consisting of two parallel pathways imprinted by solitonic ferromagnetic texturing. A specially developed staggered-grid leap-frog discretization scheme in 2 +1 dimensions with absorbing boundary conditions is employed to study the interferometer in an open device geometry. Its net transmission can be tuned from constructive to destructive interference, either by variation of the magnetization texture (effective path length) or an applied gate bias (wavelength). Possible ways to observe and utilize this effect are discussed.