Magnetic forces and stationary electron flow in three-terminal semiconductor quantum ring

TL;DR

This paper investigates how magnetic forces influence electron flow in a three-terminal quantum ring, revealing classical guidance effects, interference phenomena, and the impact of scattering and chaos on transport properties.

Contribution

It provides new insights into magnetic force effects on electron trajectories, interference conditions, and the role of scattering and chaos in quantum ring transport.

Findings

Magnetic forces guide current along classical paths at high magnetic fields.

Interference effects cause sharp peaks in transfer probability, suppressed by thermal broadening.

Elastic scattering and chaos diminish magnetic and interference effects.

Abstract

We study stationary electron flow through a three-terminal quantum ring and describe effects due to deflection of electron trajectories by classical magnetic forces. We demonstrate that generally at high magnetic field ($B$) the current is guided by magnetic forces to follow a classical path which for $B>0$ leads via the left arm of the ring to the left output terminal. The transport to the left output terminal is blocked for narrow windows of magnetic field for which the interference within the ring leads to formation of wave functions that are only weakly coupled to the output channel wave functions. These interference conditions are accompanied by injection of the current to the right arm of the ring and by appearance of sharp peaks of the transfer probability to the right output terminal. We find that these peaks at high magnetic field are attenuated by thermal widening of the transport window. We also demonstrate that the interference conditions that lead to their appearance vanish when an elastic scattering within the ring is present. The clear effect of magnetic forces on the transfer probabilities disappears along with Aharonov-Bohm oscillations in a chaotic transport regime that is found for rings whose width is larger than the width of the channels.