Twist engineering has emerged as a powerful approach for modulating electronic properties in van der Waals heterostructures. While theoretical works have predicted the modulation of spin texture in graphene-based heterostructures by twist angle, experimental studies are lacking. Here, by performing spin precession experiments, we demonstrate tunability of the spin texture and associated spin-charge interconversion with twist angle in WSe2/graphene heterostructures. For specific twist angles, we detect a spin component radial with the electron's momentum, in addition to the standard orthogonal component. Our results show that the helicity of the spin texture can be reversed by twist angle, highlighting the critical role of the twist angle in the spin-orbit properties of WSe2/graphene heterostructures and paving the way for the development of spin-twistronic devices.

Centro de Física de Materiales and Materials Physics Center Donostia San Sebastian Spain

CIC nanoGUNE BRTA Donostia San Sebastian Spain

Faculty of Mathematics and Physics Charles University Prague Czech Republic

Fert Beijing Institute MIIT Key Laboratory of Spintronics School of Integrated Circuit Science and Engineering Beihang University Beijing China

IKERBASQUE Basque Foundation for Science Bilbao Spain

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Ribeiro-Palau, R. et al. Twistable electronics with dynamically rotatable heterostructures. Science 361, 690–693 (2018). DOI

Andrei, E. Y. & MacDonald, A. H. Graphene bilayers with a twist. Nat. Mater. 19, 1265–1275 (2020). PubMed DOI

Kennes, D. M. et al. Moiré heterostructures as a condensed-matter quantum simulator. Nat. Phys. 17, 155–163 (2021). DOI

Serlin, M. et al. Intrinsic quantized anomalous Hall effect in a moiré heterostructure. Science 367, 900–903 (2020). PubMed DOI

Zheng, Z. et al. Unconventional ferroelectricity in moiré heterostructures. Nature 588, 71–76 (2020). PubMed DOI

Lin, J. X. et al. Spin–orbit-driven ferromagnetism at half moiré filling in magic-angle twisted bilayer graphene. Science 375, 437–441 (2022). PubMed DOI

Tschirhart, C. L. et al. Intrinsic spin Hall torque in a moiré Chern magnet. Nat. Phys. 19, 807–813 (2023). DOI

Tao, Z. et al. Giant spin Hall effect in AB-stacked MoTe DOI

Cao, Y. et al. Unconventional superconductivity in magic-angle graphene superlattices. Nature 556, 43–50 (2018). PubMed DOI

Sun, L. et al. Determining spin–orbit coupling in graphene by quasiparticle interference imaging. Nat. Commun. 14, 3771 (2023). PubMed DOI PMC

Ingla-Aynés, J., Meijerink, R. J. & Wees, B. J. V. Eighty-eight percent directional guiding of spin currents with 90 μm relaxation length in bilayer graphene using carrier drift. Nano Lett. 16, 4825–4830 (2016). PubMed DOI

Drögeler, M. et al. Spin lifetimes exceeding 12 ns in graphene nonlocal spin valve devices. Nano Lett. 16, 3533–3539 (2016). PubMed DOI

Yang, H. et al. Gate-tunable spin Hall effect in an all-light-element heterostructure: graphene with copper oxide. Nano Lett. 23, 4406–4414 (2023). PubMed DOI

Ontoso, N. et al. Unconventional charge-to-spin conversion in graphene/MoTe DOI

Ghiasi, T. S., Kaverzin, A. A., Blah, P. J. & Van Wees, B. J. Charge-to-spin conversion by the Rashba–Edelstein effect in two-dimensional van der Waals heterostructures up to room temperature. Nano Lett. 19, 5959–5966 (2019). PubMed DOI PMC

Gmitra, M., Kochan, D. & Fabian, J. Spin–orbit coupling in hydrogenated graphene. Phys. Rev. Lett. 110, 246602 (2013). PubMed DOI

Weeks, C., Hu, J., Alicea, J., Franz, M. & Wu, R. Engineering a robust quantum spin Hall state in graphene via adatom deposition. Phys. Rev. X 1, 021001 (2011).

Gmitra, M., Kochan, D., Högl, P. & Fabian, J. Trivial and inverted Dirac bands and the emergence of quantum spin Hall states in graphene on transition-metal dichalcogenides. Phys. Rev. B 93, 155104 (2016). DOI

Calleja, F. et al. Spatial variation of a giant spin–orbit effect induces electron confinement in graphene on Pb islands. Nat. Phys. 11, 43–47 (2015). DOI

Safeer, C. K. et al. Reliability of spin-to-charge conversion measurements in graphene-based lateral spin valves. 2D Mater. 9, 015024 (2022). DOI

Ingla-Aynés, J. et al. Omnidirectional spin-to-charge conversion in graphene/NbSe DOI

Ingla-Aynés, J., Herling, F., Fabian, J., Hueso, L. E. & Casanova, F. Electrical control of valley-Zeeman spin–orbit-coupling–induced spin precession at room temperature. Phys. Rev. Lett. 127, 047202 (2021). PubMed DOI

Herling, F. et al. Gate tunability of highly efficient spin-to-charge conversion by spin Hall effect in graphene proximitized with WSe DOI

Safeer, C. K. et al. Spin Hall effect in bilayer graphene combined with an insulator up to room temperature. Nano Lett. 20, 4573–4579 (2020). PubMed DOI

Safeer, C. K. et al. Room-temperature spin Hall effect in graphene/MoS PubMed DOI

Safeer, C. K. et al. Large multidirectional spin-to-charge conversion in low-symmetry semimetal MoTe PubMed DOI

Benítez, L. A. et al. Tunable room-temperature spin galvanic and spin Hall effects in van der Waals heterostructures. Nat. Mater. 19, 170–175 (2020). PubMed DOI

Pham, V. T. et al. Spin–orbit magnetic state readout in scaled ferromagnetic/heavy metal nanostructures. Nat. Electron. 3, 309–315 (2020). DOI

Manipatruni, S. et al. Scalable energy-efficient magnetoelectric spin–orbit logic. Nature 565, 35–42 (2019). PubMed DOI

Yang, H. et al. Two-dimensional materials prospects for non-volatile spintronic memories. Nature 606, 663–673 (2022). PubMed DOI

Lin, C. C. et al. Spin transfer torque in a graphene lateral spin valve assisted by an external magnetic field. Nano Lett. 13, 5177–5181 (2013). PubMed DOI

Cummings, A. W., Garcia, J. H., Fabian, J. & Roche, S. Giant spin lifetime anisotropy in graphene induced by proximity effects. Phys. Rev. Lett. 119, 206601 (2017). PubMed DOI

Offidani, M., Milletarì, M., Raimondi, R. & Ferreira, A. Optimal charge-to-spin conversion in graphene on transition-metal dichalcogenides. Phys. Rev. Lett. 119, 196801 (2017). PubMed DOI

Garcia, J. H., Cummings, A. W. & Roche, S. Spin Hall effect and weak antilocalization in graphene/transition metal dichalcogenide heterostructures. Nano Lett. 17, 5078–5083 (2017). PubMed DOI

Milletarì, M., Offidani, M., Ferreira, A. & Raimondi, R. Covariant conservation laws and the spin Hall effect in Dirac–Rashba systems. Phys. Rev. Lett. 119, 246801 (2017). PubMed DOI

Garcia, J. H., Vila, M., Cummings, A. W. & Roche, S. Spin transport in graphene/transition metal dichalcogenide heterostructures. Chem. Soc. Rev. 47, 3359–3379 (2018). PubMed DOI

Lee, S. et al. Charge-to-spin conversion in twisted graphene/WSe DOI

Li, Y. & Koshino, M. Twist-angle dependence of the proximity spin–orbit coupling in graphene on transition-metal dichalcogenides. Phys. Rev. B 99, 075438 (2019). DOI

Naimer, T., Zollner, K., Gmitra, M. & Fabian, J. Twist-angle dependent proximity induced spin–orbit coupling in graphene/transition metal dichalcogenide heterostructures. Phys. Rev. B 104, 195156 (2021). DOI

David, A., Rakyta, P., Kormányos, A. & Burkard, G. Induced spin–orbit coupling in twisted graphene–transition metal dichalcogenide heterobilayers: twistronics meets spintronics. Phys. Rev. B 100, 085412 (2019). DOI

Veneri, A., Perkins, D. T. S., Péterfalvi, C. G. & Ferreira, A. Twist angle controlled collinear Edelstein effect in van der Waals heterostructures. Phys. Rev. B 106, L081406 (2022). DOI

Péterfalvi, C. G., David, A., Rakyta, P., Burkard, G. & Kormányos, A. Quantum interference tuning of spin–orbit coupling in twisted van der Waals trilayers. Phys. Rev. Res. 4, L022049 (2022). DOI

Bihlmayer, G., Noël, P., Vyalikh, D. V., Chulkov, E. V. & Manchon, A. Rashba-like physics in condensed matter. Nat. Rev. Phys. 4, 642–659 (2022). DOI

Calavalle, F. et al. Gate-tuneable and chirality-dependent charge-to-spin conversion in tellurium nanowires. Nat. Mater. 21, 526–532 (2022). PubMed DOI

Camosi, L. et al. Resolving spin currents and spin densities generated by charge-spin interconversion in systems with reduced crystal symmetry. 2D Mater. 9, 035014 (2022). DOI

Li, Y. et al. Probing symmetry properties of few-layer MoS PubMed DOI

Mennel, L., Paur, M. & Mueller, T. Second harmonic generation in strained transition metal dichalcogenide monolayers: MoS DOI

You, Y., Ni, Z., Yu, T. & Shen, Z. Edge chirality determination of graphene by Raman spectroscopy. Appl. Phys. Lett. 93, 163112 (2008). DOI

Krauss, B. et al. Raman scattering at pure graphene zigzag edges. Nano Lett. 10, 4544–4548 (2010). PubMed DOI

Zollner, K., João, S. M., Nikolić, B. K. & Fabian, J. Twist- and gate-tunable proximity spin–orbit coupling, spin relaxation anisotropy, and charge-to-spin conversion in heterostructures of graphene and transition metal dichalcogenides. Phys. Rev. B 108, 235166 (2023). DOI