First-principles and model simulation of all-optical spin reversal

TL;DR

This paper introduces a first-principles computational approach to all-optical spin reversal, moving beyond semiempirical models, and predicts efficient, subpicosecond laser switching in specific magnetic materials for advanced data storage.

Contribution

It develops a first-principles and model simulation framework for laser-induced spin reversal, providing a new paradigm free of effective fields and guiding practical device design.

Findings

Predicts subpicosecond spin switching in strong ferrimagnets.

Identifies Laves phase C15 rare-earth alloys as energy-efficient candidates.

Establishes a new theoretical paradigm for ultrafast spin control.

Abstract

All-optical spin switching is a potential trailblazer for information storage and communication at an unprecedented fast rate and free of magnetic fields. However, the current wisdom is largely based on semiempirical models of effective magnetic fields and heat pulses, so it is difficult to provide high-speed design protocols for actual devices. Here, we carry out a massively parallel first-principles and model calculation for thirteen spin systems and magnetic layers, free of any effective field, to establish a simpler and alternative paradigm of laser-induced ultrafast spin reversal and to point out a path to a full-integrated photospintronic device. It is the interplay of the optical selection rule and sublattice spin orderings that underlines seemingly irreconcilable helicity-dependent/independent switchings. Using realistic experimental parameters, we predict that strong ferrimagnets, in particular, Laves phase C15 rare-earth alloys, meet the telecommunication energy requirement of 10 fJ, thus allowing a cost-effective subpicosecond laser to switch spin in the GHz region.