Surfaces and slabs of fractional topological insulator heterostructures

Abstract

Fractional topological insulators (FTIs) are electronic topological phases in (3 + 1) dimensions enriched by time reversal (TR) and charge U(1) conservation symmetries. We focus on the simplest series of fermionic FTIs, whose bulk quasiparticles consist of deconfined partons that carry fractional electric charges in integral units of e* = e/(2n + 1) and couple to a discrete Z(2n+1) gauge theory. We propose massive symmetry preserving or breaking FTI surface states. Combining the long-ranged entangled bulk with these topological surface states, we deduce the novel topological order of quasi-(2 + 1)-dimensional FTI slabs as well as their corresponding edge conformal field theories.