Energy relaxation in a quantum dot at the edge of a two-dimensional topological insulator

The calculation of energy relaxation rates due to transitions involving phonons is performed for quantum dots of varying size which are formed by magnetic barriers at the edge of a two-dimensional topological insulator based on a HgTe/CdTe quantum well. Relaxation both into the discrete and continuous spectrum of edge states is considered, as well as into the continuous spectrum of the bulk material. The obtained results demonstrate the existence of a region of system parameters which provide relatively slow energy relaxation, indicating that the considered objects are promising, e.g., for the design of novel types of solid state qubits.