Magneto-quantum oscillations of the conductance of a tunnel point-contact in the presence of a single defect

TL;DR

This paper investigates how a magnetic field affects the conductance of a tunnel point contact with a single defect, revealing magneto-quantum oscillations influenced by electron focusing and Aharonov-Bohm effects.

Contribution

It demonstrates the coexistence of two types of magneto-quantum oscillations in conductance, depending on the contact-defect distance, due to electron focusing and magnetic flux effects.

Findings

Conductance exhibits specific magneto-quantum oscillations.

Oscillation amplitude and period depend on contact-defect distance.

Non-monotonic conductance behavior results from superimposed oscillations.

Abstract

The influence of a quantizing magnetic field $H$ to the conductance of a tunnel point contact in the presence of the single defect has been considered. We demonstrate that the conductance exhibits specific magneto-quantum oscillations, the amplitude and period of which depend on the distance between the contact and the defect. We show that a non-monotonic dependence of the point-contact conductance results from a superposition of two types of oscillations: A short period oscillation arising from electron focusing by the field $H$ and a long period oscillation of Aharonov-Bohm-type originated from the magnetic flux passing through the closed trajectories of electrons moving from the contact to the defect and returning back to the contact.