Quantized Piezospintronic Effect in Moiré Systems

Fuente: arXiv
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Autores principales: Castro, Mario, Mancilla, Benjamín, Wolff, Fabian, Nunez, Alvaro S.
Formato: Preprint
Publicado: 2025
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author Castro, Mario
Mancilla, Benjamín
Wolff, Fabian
Nunez, Alvaro S.
author_facet Castro, Mario
Mancilla, Benjamín
Wolff, Fabian
Nunez, Alvaro S.
contents This paper presents a novel approach for generating and controlling spin currents in an antiferromagnetic twisted honeycomb bilayer in response to an elastic deformation. Utilizing a continuum model, closely based upon the seminal Bistritzer-MacDonald model, that captures the essential physics of low-energy moiré bands, we calculate the spin current response to the deformation in terms of the familiar Berry phase formalism. The resulting moiré superlattice potential modulates the electronic band structure, leading to emergent topological phases and novel transport properties such as quantized piezo responses both for spin and charge transport. This approach allows us to tune the system across different topological regimes and to explore the piezo-spintronic responses as a function of the band topology. When inversion symmetry is broken either by a sublattice potential $V$, alignment with an hBN substrate, uniaxial strain, or structural asymmetry present in the moiré superlattice, the system acquires a finite Berry curvature that is opposite in the $K$ and $K'$ valleys (protected by valley time reversal symmetry). In contrast, for strain, the valley-contrasting nature of the pseudo-gauge field ensures that the quantized response is robust and proportional to the sum of the valley Chern numbers. These notable physical properties make these systems promising candidates for groundbreaking spintronic and valleytronic devices.
format Preprint
id arxiv_https___arxiv_org_abs_2510_03841
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantized Piezospintronic Effect in Moiré Systems
Castro, Mario
Mancilla, Benjamín
Wolff, Fabian
Nunez, Alvaro S.
Mesoscale and Nanoscale Physics
This paper presents a novel approach for generating and controlling spin currents in an antiferromagnetic twisted honeycomb bilayer in response to an elastic deformation. Utilizing a continuum model, closely based upon the seminal Bistritzer-MacDonald model, that captures the essential physics of low-energy moiré bands, we calculate the spin current response to the deformation in terms of the familiar Berry phase formalism. The resulting moiré superlattice potential modulates the electronic band structure, leading to emergent topological phases and novel transport properties such as quantized piezo responses both for spin and charge transport. This approach allows us to tune the system across different topological regimes and to explore the piezo-spintronic responses as a function of the band topology. When inversion symmetry is broken either by a sublattice potential $V$, alignment with an hBN substrate, uniaxial strain, or structural asymmetry present in the moiré superlattice, the system acquires a finite Berry curvature that is opposite in the $K$ and $K'$ valleys (protected by valley time reversal symmetry). In contrast, for strain, the valley-contrasting nature of the pseudo-gauge field ensures that the quantized response is robust and proportional to the sum of the valley Chern numbers. These notable physical properties make these systems promising candidates for groundbreaking spintronic and valleytronic devices.
title Quantized Piezospintronic Effect in Moiré Systems
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2510.03841