Zero- and one-dimensional magnetic traps for quasi-particles

TL;DR

This paper explores how different shaped micromagnets can create zero- and one-dimensional magnetic traps for quasi-particles with spin in hybrid structures, enabling potential optical detection of localized states.

Contribution

It demonstrates the creation of zero- and one-dimensional spin traps using cylindrical and rectangular micromagnets, with detailed analysis of magnetic field profiles and optical detection methods.

Findings

Micro-disk micromagnets produce zero-dimensional localized states.

Rectangular micromagnets generate one-dimensional states with free movement in one direction.

Discrete localized states can be detected via low temperature optical measurements.

Abstract

We investigate the possibility of trapping quasi-particles possessing spin degree of freedom in hybrid structures. The hybrid system we are considering here is composed of a semi-magnetic quantum well placed a few nanometers below a ferromagnetic micromagnet. We are interested in two different micromagnet shapes: cylindrical (micro-disk) and rectangular geometry. We show that in the case of a micro-disk, the spin object is localized in all three directions and therefore zero-dimensional states are created, and in the case of an elongated rectangular micromagnet, the quasi-particles can move freely in one direction, hence one-dimensional states are formed. After calculating profiles of the magnetic field produced by the micromagnets, we analyze in detail the possible light absorption spectrum for different micromagnet thicknesses, and different distances between the micromagnet and the semimagnetic quantum well. We find that the discrete spectrum of the localized states can be detected via spatially-resolved low temperature optical measurement.