Ultrafast light-induced magnetization in non-magnetic films: from orbital and spin Hall phenomena to the inverse Faraday effect

TL;DR

This paper demonstrates how ultrafast laser pulses can induce significant orbital and spin magnetizations in non-magnetic platinum films through mechanisms like the orbital Hall effect and inverse Faraday effect, opening new avenues for light-based magnetic information encoding.

Contribution

It reveals the magnetic response of non-magnetic materials to ultrafast light, highlighting the roles of orbital and spin phenomena in magnetization generation.

Findings

Significant orbital and spin magnetizations are generated in platinum films.

The orbital Hall effect and inverse Faraday effect are key mechanisms.

Light can encode magnetic information in non-magnetic materials.

Abstract

The field of orbitronics has emerged with great potential to impact information technology by enabling environmentally friendly electronic devices. The main electronic degree of freedom at play is the orbital angular momentum, which can give rise to a myriad of phenomena such as the orbital Hall effect (OHE), torques and orbital magnetoelectric effects. Here, we explore via realistic time-dependent electronic structure simulations the magnetic response of a non-magnetic material, an ultrathin Pt film, to ultrafast laser pulses of different polarizatons and helicities. We demonstrate the generation of significant orbital and spin magnetizations and identify the underlying mechanisms consisting of the interplay of the OHE, inverse Faraday effect and spin-orbit interaction. Our discoveries advocate for the prospect of encoding magnetic information using light in materials that are not inherently magnetic.