Multiple scattering theory of quasiparticles on a topological insulator surface

We develop a general multiple-scattering partial-wave theory for topological insulator (TI) surfaces and derive cross sections (CSs) for single- and two-centered scattering. We show that on gapped TI surfaces the symmetry of the differential CS is reduced, and that backscattering occurs. A sharp resonance peak in the total CS Λtot of heights 30–55 nm is found at the band edge ∼50 meV, which could be useful in determining energy gaps on TI surfaces. Interference effects are obvious in CSs from quasiparticle scattering off two scattering centers, and additional resonance peaks are introduced in Λtot around ∼233 meV associated with higher-order partial-waves.