Microscopic Theory of Ultrafast Skyrmion Excitation by Light

TL;DR

This paper presents a microscopic theory explaining how ultrafast laser pulses can generate skyrmions within 100 femtoseconds through electronic and spin interactions mediated by Rashba spin-orbit coupling.

Contribution

It introduces a detailed microscopic model for laser-induced skyrmion creation, highlighting the role of electronic currents and spin-orbit interactions in the process.

Findings

Skyrmions can be nucleated within 100 fs by optical excitation.

The mechanism involves coupling between electronic currents and magnetic moments.

Rashba spin-orbit interaction mediates the ultrafast skyrmion excitation.

Abstract

We propose a microscopic mechanism for ultrafast skyrmion photo-excitation via a two-orbital electronic model. In the strong correlation limit the $d$-electrons are described by an effective spin Hamiltonian, coupled to itinerant $s$-electrons via $s-d$ exchange. Laser-exciting the system by a direct coupling to the electric charge leads to skyrmion nucleation on a 100 fs timescale. The coupling between photo-induced electronic currents and magnetic moments, mediated via Rashba spin-orbit interactions, is identified as the microscopic mechanism behind the ultrafast optical skyrmion excitation.