Theory of charge-to-spin conversion under quantum confinement

Alfonso Maiellaro; Francesco Romeo; Mattia Trama; Irene Gaiardoni; Jacopo Settino; Claudio Guarcello; Nicolas Bergeal; Manuel Bibes; Roberta Citro

doi:10.1103/zpvy-t4d4

arXiv · 2505.12819

Theory of charge-to-spin conversion under quantum confinement

Alfonso Maiellaro·Francesco Romeo·Mattia Trama·Irene Gaiardoni·Jacopo Settino·Claudio Guarcello·Nicolas Bergeal·Manuel Bibes·Roberta Citro

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Abstract

The interplay between spin and charge degrees of freedom in low-dimensional systems is a cornerstone of modern spintronics, where achieving all-electrical control of spin currents is a major goal. Spin-orbit interactions provide a promising mechanism for such control, yet understanding how spin and charge transport emerge from microscopic principles remains a fundamental challenge. Here we develop a spin-dependent scattering matrix approach to describe spin and charge transport in a multiterminal system in the presence of Rashba spin-orbit interaction. Our framework generalizes the B\"uttiker formalism by offering explicit real-space expressions for spin and charge current densities, along with the corresponding linear response function. It simultaneously captures the effects of quantum confinement, the orbital response to external magnetic fields, and the intrinsic (geometric) properties of the electronic bands, offering a comprehensive description of the spin-charge interconversion mechanisms at play in a Hall bar, in agreement with experiments.

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Alfonso Maiellaro, Francesco Romeo, Mattia Trama, Irene Gaiardoni, Jacopo Settino, Claudio Guarcello, Nicolas Bergeal, Manuel Bibes, Roberta Citro. 2025-05-19. Theory of charge-to-spin conversion under quantum confinement. https://doi.org/10.1103/zpvy-t4d4

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