Electrically driven Rabi dynamics of magnetic field induced corner states in a two-dimensional topological insulator
Phys. Rev. B 114, 225414 – Published 19 October, 2026
DOI: https://doi.org/10.1103/4ns8-7kd4
Abstract
We study coherent electric manipulation of magnetic field induced localized states at a double kink of a helical edge in a HgTe/CdHgTe quantum well. An in-plane magnetic field opens a gap in the one-dimensional (1D) edge spectrum, while changes in the edge orientation generate localized in-gap states at the kinks. We show that, for suitable geometry and magnetic field direction, two such states form an effective lithographically defined two-level subsystem. Using an edge-state model that includes both the localized levels and the fully propagating 1D edge states outside the magnetic field induced gap, we calculate the electric-dipole matrix elements and solve the time-dependent problem under resonant driving. The resulting dynamics exhibits Rabi oscillations with linear frequencies of 20–40 GHz for realistic parameters. We find that the propagating 1D edge states provide a leakage channel whose strength is strongly controlled by the driving amplitude: reducing the electric field suppresses leakage below the percent level while preserving GHz-scale coherent oscillations. These results establish a route from magnetic field induced corner-state physics to electrically driven two-level dynamics in a realistic two-dimensional topological-insulator edge geometry.
