Electron heating and current scaling in a two-dimensional electron system in close proximity to nanoscale scatterers

Abstract

We have performed magneto-transport measurements on a two-dimensional electron system (2DES) which is in close proximity to nanoscaled scatterers. Weak localization, as evidenced by negative magnetoresistance, is observed. In this work, we use the extracted phase coherence rate as a thermometer to measure the electron's effective temperature T (e) in our 2DES when a high driving current I flows through the device. We find that T (e) ae I (similar to 0.52), consistent with 1/tau (ep) similar to T (2) in two dimensions, where 1/tau (ep) is the electron-phonon scattering rate. However, the phase coherence rate 1/tau (phi) similar to T, with a very small offset, is consistent with zero-temperature dephasing. Most importantly, our experimental results are in agreement with the fact that at low temperatures, the dominant phase-breaking mechanism is electron-electron scattering, not electron-phonon scattering. Therefore we are able to investigate both electron-electron scattering and electron-phonon scattering which are, in most cases, difficult to study independently in the linear region. Our data show that the electron heating effect is a very powerful tool for studying semiconductor devices.