Laser-induced spin protection and switching in a specially designed magnetic dot: A theoretical investigation

TL;DR

This theoretical study predicts that specially designed magnetic dots can use laser pulses to protect or switch their spin states through electromagnetically induced transparency and population inversion, offering new control methods for nanoscale magnetism.

Contribution

It introduces a novel approach for spin protection and switching in magnetic dots using laser-induced transparency and population inversion, extending femtosecond magnetism control to nanostructures.

Findings

Electromagnetically induced transparency can prevent spin reduction.

Population inversion enables spin switching after 60 fs delay.

Predictions are experimentally testable.

Abstract

Most laser-induced femtosecond magnetism investigations are done in magnetic thin films. Nanostructured magnetic dots, with their reduced dimensionality, present new opportunities for spin manipulation. Here we predict that if a magnetic dot has a dipole-forbidden transition between the lowest occupied molecular orbital (LUMO) and the highest unoccupied molecular orbital (HOMO), but a dipole-allowed transition between LUMO+1 and HOMO, electromagnetically inducedtransparency can be used to prevent ultrafast laser-induced spin momentum reduction, or spin protection. This is realized through a strong dump pulse to funnel the population into LUMO+1. If the time delay between the pump and dump pulses is longer than 60 fs, a population inversion starts and spin switching is achieved. Thesepredictions are detectable experimentally.