Giant moment increase by ultrafast laser light

Fuente: arXiv
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Main Authors: Sharma, Sangeeta, Gill, Deepika, Krishna, Jyoti, Harris-Lee, Eddie, Dewhurst, John Kay, Shallcross, Sam
Format: Preprint
Published: 2025
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author Sharma, Sangeeta
Gill, Deepika
Krishna, Jyoti
Harris-Lee, Eddie
Dewhurst, John Kay
Shallcross, Sam
author_facet Sharma, Sangeeta
Gill, Deepika
Krishna, Jyoti
Harris-Lee, Eddie
Dewhurst, John Kay
Shallcross, Sam
contents It is now well established that a few femtosecond laser pulse will induce an ultrafast loss of moment in a magnetic material. Here we show that the opposite effect can also occur: an ultrafast increase in moment. Employing both tight-binding and state-of-the-art time dependent density functional theory we find that laser light tuned to the majority spin conduction band in the 2d magnets CrI$_3$ and CrSBr generates an ultrafast giant moment increase, of up to 33\% in the case of CrI$_3$ (2~$μ_B$). Underpinning this is spin-orbit induced valence band spin texture that, in combination with a strong field light pulse, facilitates an optical spin flip transition involving both intra- and inter-band excitation. Our findings, that establish a general mechanism by which ultrafast light pulses may enhance as well as decrease the magnetic moment, point towards rich possibilities for light control over magnetic matter at femtosecond times.
format Preprint
id arxiv_https___arxiv_org_abs_2503_02396
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Giant moment increase by ultrafast laser light
Sharma, Sangeeta
Gill, Deepika
Krishna, Jyoti
Harris-Lee, Eddie
Dewhurst, John Kay
Shallcross, Sam
Materials Science
Other Condensed Matter
Optics
Quantum Physics
It is now well established that a few femtosecond laser pulse will induce an ultrafast loss of moment in a magnetic material. Here we show that the opposite effect can also occur: an ultrafast increase in moment. Employing both tight-binding and state-of-the-art time dependent density functional theory we find that laser light tuned to the majority spin conduction band in the 2d magnets CrI$_3$ and CrSBr generates an ultrafast giant moment increase, of up to 33\% in the case of CrI$_3$ (2~$μ_B$). Underpinning this is spin-orbit induced valence band spin texture that, in combination with a strong field light pulse, facilitates an optical spin flip transition involving both intra- and inter-band excitation. Our findings, that establish a general mechanism by which ultrafast light pulses may enhance as well as decrease the magnetic moment, point towards rich possibilities for light control over magnetic matter at femtosecond times.
title Giant moment increase by ultrafast laser light
topic Materials Science
Other Condensed Matter
Optics
Quantum Physics
url https://arxiv.org/abs/2503.02396