Enlarged magnetic focusing radius of photoinduced ballistic currents

TL;DR

This paper investigates how photoinduced ballistic electron currents in GaAs quantum point contacts exhibit a magnetic focusing radius much larger than the classical cyclotron radius, revealing new insights into electron interactions.

Contribution

The study demonstrates that the magnetic focusing radius of photoinduced currents exceeds classical predictions, highlighting the role of electron-electron scattering.

Findings

Measured focusing radius exceeds classical cyclotron radius

Monte Carlo simulations indicate electron-electron scattering as key factor

Photoinduced currents show larger trajectories than charge transport experiments

Abstract

We exploit GaAs-based quantum point contacts as mesoscopic detectors to analyze the ballistic flow of photogenerated electrons in a two-dimensional electron gas at a perpendicular magnetic field. Whereas charge transport experiments always measure the classical cyclotron radius, we show that this changes dramatically when detecting the photoinduced non-equilibrium current in magnetic fields. The experimentally determined radius of the trajectories surprisingly exceeds the classical cyclotron value by far. Monte Carlo simulations suggest electron-electron scattering as the underlying reason.