Programmable Bulk Topological Channels via Strain Engineering

Accumulated disorder at physical boundaries prevents the realization of ideal zero-dissipation topological edge channels. Here, we propose a strain engineering mechanism to create a topological domain wall in the pristine material bulk, thereby generating interior chiral channels spatially decoupled from physical boundaries. Quantum transport simulations reveal that these interior channels exhibit exceptional immunity to severe boundary disorder, maintaining an ideal vortex-free transport morphology. Furthermore, the spatial position and confinement of these interior channels can be quantitatively programmed. Under a linear gradient strain field, the channel width obeys an inverse square-root scaling law with respect to the strain gradient. In a high-Chern-number phase (|C|=2), we design the spatial splitting and merging of co-propagating chiral channels, suggesting a topological Mach-Zehnder-like geometry. These results suggest a route toward programmable bulk topological transport and reconfigurable topological circuitry.