Phonon detection using quasi one-dimensional quantum wires

We show that quasi-one-dimensional quantum wires fabricated using GaAs/AlGaAs heterostructures can be used to detect near THz acoustic phonons in the presence of magnetic field. A ballistic beam of phonons generated either electrically or optically at the backside of the substrate causes a transient change in the resistance of the quantum wire. The transient response is strongly dependent on the magnetic field, and is most likely caused by the absorption of phonons by edge states.