Controlling photo-excited electron-spin by light-polarization in ultrafast-pumped altermagnets

Fuente: arXiv
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Main Authors: Eskandari-asl, Amir, Facio, Jorge I., Janson, Oleg, Avella, Adolfo, Brink, Jeroen van den
Format: Preprint
Published: 2025
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author Eskandari-asl, Amir
Facio, Jorge I.
Janson, Oleg
Avella, Adolfo
Brink, Jeroen van den
author_facet Eskandari-asl, Amir
Facio, Jorge I.
Janson, Oleg
Avella, Adolfo
Brink, Jeroen van den
contents Altermagnets (AMs) constitute a novel class of spin-compensated materials in which the symmetry connecting opposite-spin sublattices involves a spatial rotation. Here, we uncover a set of unique non-linear, light-driven properties that set AMs apart from traditional ferro- and antiferromagnets. We demonstrate theoretically that the polarization of an electromagnetic pulse that photo-excites electrons and holes in an AM, controls the spin orientation of these non-equilibrium charge carriers. For a d-wave AM model and a prototype material, we show that very large post-pump spin polarizations may be attained by exploiting resonances. We show that this protocol also allows, in an AM, to directly probe the spin splitting of the electronic states in energy and momentum space. Thus, it can be used to identify and characterize altermagnetic materials via ultrafast pump-probe Kerr/Faraday spectroscopy or spin- and time-resolved ARPES. This opens up the possibility of devising ultrafast optical switches of non-equilibrium spin-polarization, finely tunable by adjusting the pump-pulse characteristics.
format Preprint
id arxiv_https___arxiv_org_abs_2504_01640
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Controlling photo-excited electron-spin by light-polarization in ultrafast-pumped altermagnets
Eskandari-asl, Amir
Facio, Jorge I.
Janson, Oleg
Avella, Adolfo
Brink, Jeroen van den
Materials Science
Altermagnets (AMs) constitute a novel class of spin-compensated materials in which the symmetry connecting opposite-spin sublattices involves a spatial rotation. Here, we uncover a set of unique non-linear, light-driven properties that set AMs apart from traditional ferro- and antiferromagnets. We demonstrate theoretically that the polarization of an electromagnetic pulse that photo-excites electrons and holes in an AM, controls the spin orientation of these non-equilibrium charge carriers. For a d-wave AM model and a prototype material, we show that very large post-pump spin polarizations may be attained by exploiting resonances. We show that this protocol also allows, in an AM, to directly probe the spin splitting of the electronic states in energy and momentum space. Thus, it can be used to identify and characterize altermagnetic materials via ultrafast pump-probe Kerr/Faraday spectroscopy or spin- and time-resolved ARPES. This opens up the possibility of devising ultrafast optical switches of non-equilibrium spin-polarization, finely tunable by adjusting the pump-pulse characteristics.
title Controlling photo-excited electron-spin by light-polarization in ultrafast-pumped altermagnets
topic Materials Science
url https://arxiv.org/abs/2504.01640