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arXiv · 2608.26364

Laser-Induced Rashba Spin-Orbit Torques in Multiferroic Semiconductor (Ge,Mn)Te

Zeynab Sadeghi·Tomas Ostatnicky·Eva Schmoranzerova·Jozef Kimak·Dominik Kriegner·Helena Reichlova·Lukas Nadvornik·Gunther Sprinhgholtz·J. Hugo Dil·Juraj Krempasky·Petr Nemec
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Abstract

The multiferroic semiconductor GeMnTe exhibits ferroelectricity, strong Rashba spin-orbit coupling, and carrier-mediated magnetic order, making it a unique platform for exploring the interplay among electronic, structural, and magnetic degrees of freedom. In this study, we investigate the ultrafast magnetization dynamics of Ge0.85Mn0.15Te using time-resolved magneto-optical spectroscopy. By separating magnetic and nonmagnetic contributions in the transient response, we identify two distinct laser-induced magnetic phenomena, both resulting from photoinduced effective spin-orbit torque. Coherent magnetization precession arises from a laser-induced increase in hole concentration, which modifies the occupation of Rashba-split spin-locked valence band states and alters the magnetic easy axis. The transient change in magnetic ordering, observed as variations in the coercive field, is attributed to laser-induced modifications of the ferroelectric sublattice displacement, which affect the ferroelectric polarization and the associated Rashba spin-orbit interaction. While the first type of optical spin-orbit torque has already been observed in the diluted magnetic semiconductor (Ga,Mn)As, the second effect is unique to the multiferroic Rashba semiconductor (Ge,Mn)Te, opening new opportunities for all-optical manipulation of magnetic order and spin-orbit torque generation in spin-orbitronic devices.

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Zeynab Sadeghi, Tomas Ostatnicky, Eva Schmoranzerova, Jozef Kimak, Dominik Kriegner, Helena Reichlova, Lukas Nadvornik, Gunther Sprinhgholtz, J. Hugo Dil, Juraj Krempasky, Petr Nemec. 2026-08-26. Laser-Induced Rashba Spin-Orbit Torques in Multiferroic Semiconductor (Ge,Mn)Te. https://arxiv.org/abs/2608.26364

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