Ultrafast all-optical generation of pure spin and valley currents

Fuente: arXiv
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Main Authors: Gill, Deepika, Sharma, Sangeeta, Shallcross, Sam
Format: Preprint
Published: 2024
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author Gill, Deepika
Sharma, Sangeeta
Shallcross, Sam
author_facet Gill, Deepika
Sharma, Sangeeta
Shallcross, Sam
contents Pure currents comprise the flow of a two state quantum freedom -- for example the electron spin -- in the absence of charge flow. Radically different from the charge currents that underpin present day electronics, in two dimensional materials possessing additional two state freedoms such as valley index they offer profound possibilities for miniaturization and energy efficiency in a next generation spin- and valley- tronics. Here we demonstrate a robust multi-pump light wave protocol capable of generating both pure spin and valley currents on femtosecond times. The generation time is determined by the 2d material gap, with the creation of pure spin current in WSe2 at 40 fs and pure valley current in bilayer graphene at ~200 fs. Our all-optical approach demands no special material design, requiring only a gapped valley active material, and is thus applicable to a wide range of 2d materials.
format Preprint
id arxiv_https___arxiv_org_abs_2411_02371
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ultrafast all-optical generation of pure spin and valley currents
Gill, Deepika
Sharma, Sangeeta
Shallcross, Sam
Mesoscale and Nanoscale Physics
Materials Science
Pure currents comprise the flow of a two state quantum freedom -- for example the electron spin -- in the absence of charge flow. Radically different from the charge currents that underpin present day electronics, in two dimensional materials possessing additional two state freedoms such as valley index they offer profound possibilities for miniaturization and energy efficiency in a next generation spin- and valley- tronics. Here we demonstrate a robust multi-pump light wave protocol capable of generating both pure spin and valley currents on femtosecond times. The generation time is determined by the 2d material gap, with the creation of pure spin current in WSe2 at 40 fs and pure valley current in bilayer graphene at ~200 fs. Our all-optical approach demands no special material design, requiring only a gapped valley active material, and is thus applicable to a wide range of 2d materials.
title Ultrafast all-optical generation of pure spin and valley currents
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2411.02371