ELECTRON - LO-PHONON SCATTERING RATES IN A CYLINDRICAL QUANTUM-WIRE WITH AN AXIAL MAGNETIC-FIELD - ANALYTIC RESULTS

The interaction of electrons with bulk LO phonons in a cylindrical qua ntum wire is discussed with both intersubband and intrasubband relaxat ion considered. For processes involving the lowest pair of subbands, a parallel analytic approach leads to good agreement with the numerical calculations. In particular, the effect of an axial magnetic field is determined for intersubband transitions between these two subbands. I t is found that for a given radius, there is a critical magnetic field beyond which first-order LO-phonon interactions are forbidden due to energy conservation. Close to the critical fields, fast intersubband r elaxation is predicted. These effects are a consequence of the Zeeman splitting of the doubly degenerate states in the presence of the field and the behavior of the one-dimensional density of states.