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arXiv · 2505.23237

Optical Controllable Spin-Polarization in Two Dimensional Altermagnets via Robust Spin-Momentum Locking Excitons

Jiuyu Sun·Jinzhe Han·Yongping Du·Erjun Kan
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Abstract

Spin-momentum locking (SML) excitons in two-dimensional semiconductors are appealing to programmable optical control of spin-polarized carriers in ultrafast spintronics. To address the current thirsty for long-lived excitons with zero-external-field stability and room-temperature spin-polarization, we hereby predict the existence of intrinsically SML excitons in altermagnetic V$_2 X_2$O ($X=$ S, Se) driven by giant non-relativistic spin-splittings ($>$ 1.2 eV). First-principles calculations reveal SML excitons with binding energies exceeding 1400 meV in monolayers and 430 meV in their van der Waals heterobilayers, along with stacking-dependent optical selection rules for tunable interlayer excitons. These remarkable physical properties, combined with their long radiative lifetimes, strongly suggest the feasibility of SML excitons with robust spin-polarization at room temperature. Our work provides a new paradigm for SML exciton physics via the novel altermagnetism, opening up new possibilities for all-optical manipulation in advanced opto-spintronics.

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Jiuyu Sun, Jinzhe Han, Yongping Du, Erjun Kan. 2025-05-29. Optical Controllable Spin-Polarization in Two Dimensional Altermagnets via Robust Spin-Momentum Locking Excitons. https://arxiv.org/abs/2505.23237

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