The all-electrical realization of highly spin-polarized charge currents and their efficient conversion into pure spin currents remains a fundamental challenge in spintronics. Here, we report a spin-axis dynamic locking (SADL) effect in altermagnets that pins the spin polarization to the crystalline axes: an in-plane electric field along one principal axis drives a fully spin-up charge current, whereas along the orthogonal axis, it generates an equal spin-down current. Consequently, applying an electric field diagonally yields a transverse pure spin current with 100% charge-to-spin conversion efficiency. Mechanistically, SADL originates in a distinctive tent state characterized by alternating spin-split flat bands and orthogonal Fermi-surface lines. High-throughput first-principles screening confirms SADL in broad materials (e.g., 2D Cr2WSe4 monolayer and a synthesized three-dimensional compound, (BaF)2Mn2Se2O). Our work thus opens a route to ultra-low-power, reconfigurable spintronic devices where the spin states are governed solely by electric field orientation.
@article{arxiv.2509.18476,
title = {Spin-Axis Dynamic Locking},
author = {Lv Zhiheng and Cai Jiangtao and Ma Dengpan and Xing Yan and Liu Zhifeng},
journal= {arXiv preprint arXiv:2509.18476},
year = {2025}
}