Ultrafast Spin Injection in Graphene via Dynamical Carrier Filtering at Transition Metal Dichalcogenide Interfaces

Fuente: arXiv
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Autori principali: Yamada, Shunsuke, Hashmi, Arqum, Otobe, Tomohito
Natura: Preprint
Pubblicazione: 2025
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author Yamada, Shunsuke
Hashmi, Arqum
Otobe, Tomohito
author_facet Yamada, Shunsuke
Hashmi, Arqum
Otobe, Tomohito
contents We report a real-time first-principles study of ultrafast spin injection in a WSe$_2$-graphene heterobilayer under circularly polarized laser irradiation, using time-dependent density functional theory. Contrary to conventional expectations, spin transfer into graphene is not a passive process but is actively driven by spin-selective carrier filtering at the interface. Spin-polarized carriers generated in the WSe$_2$ layer induce a preferential migration of opposite-spin carriers from graphene, which results in net spin magnetization in graphene. This process is governed by interlayer band offsets, density-of-state asymmetry, and Pauli blocking. These findings indicate a microscopic mechanism of spin injection in non-magnetic systems and identify a guiding principle for the design of ultrafast opto-spintronic functionalities in van der Waals heterostructures.
format Preprint
id arxiv_https___arxiv_org_abs_2509_08339
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ultrafast Spin Injection in Graphene via Dynamical Carrier Filtering at Transition Metal Dichalcogenide Interfaces
Yamada, Shunsuke
Hashmi, Arqum
Otobe, Tomohito
Materials Science
We report a real-time first-principles study of ultrafast spin injection in a WSe$_2$-graphene heterobilayer under circularly polarized laser irradiation, using time-dependent density functional theory. Contrary to conventional expectations, spin transfer into graphene is not a passive process but is actively driven by spin-selective carrier filtering at the interface. Spin-polarized carriers generated in the WSe$_2$ layer induce a preferential migration of opposite-spin carriers from graphene, which results in net spin magnetization in graphene. This process is governed by interlayer band offsets, density-of-state asymmetry, and Pauli blocking. These findings indicate a microscopic mechanism of spin injection in non-magnetic systems and identify a guiding principle for the design of ultrafast opto-spintronic functionalities in van der Waals heterostructures.
title Ultrafast Spin Injection in Graphene via Dynamical Carrier Filtering at Transition Metal Dichalcogenide Interfaces
topic Materials Science
url https://arxiv.org/abs/2509.08339