We propose and analyze a general scheme to create chiral topological edge
modes within the bulk of two-dimensional engineered quantum systems. Our method
is based on the implementation of topological interfaces, designed within the
bulk of the system, where topologically-protected edge modes localize and
freely propagate in a unidirectional manner. This scheme is illustrated through
an optical-lattice realization of the Haldane model for cold atoms, where an
additional spatially-varying lattice potential induces distinct topological
phases in separated regions of space. We present two realistic experimental
configurations, which lead to linear and radial-symmetric topological
interfaces, which both allows one to significantly reduce the effects of
external confinement on topological edge properties. Furthermore, the
versatility of our method opens the possibility of tuning the position, the
localization length and the chirality of the edge modes, through simple
adjustments of the lattice potentials. In order to demonstrate the unique
detectability offered by engineered interfaces, we numerically investigate the
time-evolution of wave packets, indicating how topological transport
unambiguously manifests itself within the lattice. Finally, we analyze the
effects of disorder on the dynamics of chiral and non-chiral states present in
the system. Interestingly, engineered disorder is shown to provide a powerful
tool for the detection of topological edge modes in cold-atom setups.Comment: 18 pages, 21 figure
