| Here, I present a detailed analysis and discussion of acoustoelectric current and the behavior of said current under the influence of a magnetic field and its interactions with quantum point contacts (QPCs). The QPCs lie on a suspended nano-bridge, which acts as an acoustic waveguide, allowing a stronger electron-phonon coupling; and hence, a larger acoustoelectric current with amplified conductance effects at a high temperature of 4.2 K.;The acoustoelectric current is first studied under the influence of a perpendicular magnetic field. Through this measurement a theoretical model was developed to accurately describe and reproduce the measurement trend; showing how the acoustoelectric current is strongly dependent on the surface acoustic wave (SAW) attenuation and the two dimensional electron gas (2DEG) conductance changes under such conditions. The next set of measurements focus on the acoustoelectric current and its interactions with the potential created by applying a negative bias to the QPCs. Here, the electronically confined region gives rise to enhanced electron-phonon interactions which manifest themselves as a change in acoustoelectric current polarity, due to phonon back scattering, and enhanced oscillations in the measured current due to subband depopulation and the change in the potential landscape.;Further information is provided such as fabrication steps, theoretical background on QPCs and SAWs, additional information of SAW-QPC interactions under the influence of a magnetic field, and phase locked acoustoelectric current with QPC pinch off. |
