Radiation of acoustic phonons from quantum wires

We have investigated by the Monte Carlo technique the radiation of ballistic acoustic phonons from quasi-one-dimensional electron gas in quantum wires. At low temperatures and over a wide range of electric fields, all excess heat in quantum wires is dissipated by means of acoustic phonons. Due to the uncertainty of momentum conservation during electron-acoustic-phonon scattering, electrons emit acoustic phonons with large transverse momentum components. Consequently, in this transport regime quantum wires radiate fluxes of nonequilibrium acoustic phonons into surrounding material. Nonequilibrium acoustic phonons can propagate ballistically over macroscopic distances. Ballistic fluxes of nonequilibrium acoustic phonons have been previously detected experimentally in quantum well structures. We have calculated the angular and energy spectrum of nonequilibrium acoustic phonons radiated from quantum wires.