Quantum states in a magnetic anti-dot

TL;DR

This paper investigates a novel magnetic anti-dot system where electrons are confined by a non-uniform magnetic field, revealing unique magnetic properties, current behaviors, and spectral features due to the system's quantum confinement and coupling effects.

Contribution

It introduces a new magnetic anti-dot system with discrete electron filling, opposite circulating currents, and spectral features that violate Kohn's theorem, expanding understanding of magnetic confinement effects.

Findings

Electron confinement in the anti-dot varies discretely with magnetic field.

Circulating currents inside and outside the anti-dot can oppose each other.

Absorption spectrum shows peaks that violate Kohn's theorem.

Abstract

We study a new system in which electrons in two dimensions are confined by a non homogeneous magnetic field. The system consists of a heterostructure with on top of it a superconducting disk. We show that in this system electrons can be confined into a dot region. This magnetic anti-dot has the interesting property that the filling of the dot is a discrete function of the magnetic field. The circulating electron current inside and outside the anti-dot can be in opposite direction for certain bound states. And those states exhibit a diamagnetic to paramagnetic transition with increasing magnetic field. The absorption spectrum consists of many peaks, some of which violate Kohn's theorem, and which is due to the coupling of the center of mass motion with the other degrees of freedom.