Fully compensated ferrimagnets (CFiMs) represent a novel class of magnetic materials that combine zero net magnetization with strong spin polarization, offering considerable potential for spintronic applications. Here, we employ real-time time-dependent density functional theory (rt-TDDFT) to investigate ultrafast laser-induced spin dynamics in a two-dimensional (2D) Janus NiICl bilayer. The broken inversion symmetry gives rise to an asymmetric interlayer demagnetization process, leading to a transient net magnetization in this system within 50 fs. This phenomenon is attributed to the asymmetric charge accumulation and interlayered optically induced spin transfer (OISTR) between the two Ni magnetic sublattices, facilitated by the intrinsic structural and electronic asymmetry of the Janus configurations. The asymmetric interlayer interaction effectively leads to a transient ferrimagnetic state. Our work reveals the microscopic mechanism of the ultrafast spin dynamics of 2D CFiMs induced by lasers in ultrafast spintronics.

Department of Physical and Macromolecular Chemistry Faculty of Science Charles University Prague 12843 Czech Republic

Institute for Advanced Study Chengdu University Chengdu 610106 China

School of Electronic Engineering Xi'an University of Posts and Telecommunications Xi'an 710121 China

School of Science Constructor University Bremen 28759 Germany

Zobrazit více v PubMed

Žutić I., Fabian J., Das Sarma S.. Spintronics: Fundamentals and applications. Rev. Mod. Phys. 2004;76:323–410. doi: 10.1103/RevModPhys.76.323. DOI

Gong C., Li L., Li Z., Ji H., Stern A., Xia Y., Cao T., Bao W., Wang C., Wang Y., Qiu Z. Q., Cava R. J., Louie S. G., Xia J., Zhang X.. Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals. Nature. 2017;546:265–269. doi: 10.1038/nature22060. PubMed DOI

Huang B., Clark G., Navarro-Moratalla E., Klein D. R., Cheng R., Seyler K. L., Zhong D., Schmidgall E., McGuire M. A., Cobden D. H., Yao W., Xiao D., Jarillo-Herrero P., Xu X.. Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit. Nature. 2017;546:270–273. doi: 10.1038/nature22391. PubMed DOI

Wolf S. A., Awschalom D. D., Buhrman R. A., Daughton J. M., von Molnár S., Roukes M. L., Chtchelkanova A. Y., Treger D. M.. Spintronics: a spin-based electronics vision for the future. Science. 2001;294:1488–1495. doi: 10.1126/science.1065389. PubMed DOI

Němec P., Fiebig M., Kampfrath T., Kimel A. V.. Antiferromagnetic opto-spintronics. Nat. Phys. 2018;14:229–241. doi: 10.1038/s41567-018-0051-x. DOI

Fukami S., Lorenz V. O., Gomonay O.. Antiferromagnetic spintronics. J. Appl. Phys. 2020;128:070401. doi: 10.1063/5.0023614. DOI

Šmejkal L., Sinova J., Jungwirth T.. Emerging Research Landscape of Altermagnetism. Physical Review X. 2022;12:040501. doi: 10.1103/PhysRevX.12.040501. DOI

Zhou X., Feng W., Zhang R.-W., Šmejkal L., Sinova J., Mokrousov Y., Yao Y.. Crystal Thermal Transport in Altermagnetic RuO2 . Phys. Rev. Lett. 2024;132:056701. doi: 10.1103/PhysRevLett.132.056701. PubMed DOI

Bai L., Feng W., Liu S., Šmejkal L., Mokrousov Y., Yao Y.. Altermagnetism: Exploring New Frontiers in Magnetism and Spintronics. Adv. Funct. Mater. 2024;34:2409327. doi: 10.1002/adfm.202409327. DOI

Mazin I.. Editorial: Altermagnetism---A New Punch Line of Fundamental Magnetism. Physical Review X. 2022;12:040002. doi: 10.1103/PhysRevX.12.040002. DOI

Liu Y., Guo S.-D., Li Y., Liu C.-C.. Two-Dimensional Fully Compensated Ferrimagnetism. Phys. Rev. Lett. 2025;134:116703. doi: 10.1103/PhysRevLett.134.116703. PubMed DOI

van Leuken H., de Groot R. A.. Half-Metallic Antiferromagnets. Phys. Rev. Lett. 1995;74:1171–1173. doi: 10.1103/PhysRevLett.74.1171. PubMed DOI

Akai H., Ogura M.. Half-Metallic Diluted Antiferromagnetic Semiconductors. Phys. Rev. Lett. 2006;97:026401. doi: 10.1103/PhysRevLett.97.026401. PubMed DOI

Wang P., Wu D., Zhang K., Wu X.. Two-Dimensional Quaternary Transition Metal Sulfide CrMoA2S6 (A = C, Si, or Ge): A Bipolar Antiferromagnetic Semiconductor with a High Néel Temperature. J. Phys. Chem. Lett. 2022;13:3850–3856. doi: 10.1021/acs.jpclett.2c00836. PubMed DOI

Siegrist F., Gessner J. A., Ossiander M., Denker C., Chang Y.-P., Schröder M. C., Guggenmos A., Cui Y., Walowski J., Martens U., Dewhurst J. K., Kleineberg U., Münzenberg M., Sharma S., Schultze M.. Light-wave dynamic control of magnetism. Nature. 2019;571:240–244. doi: 10.1038/s41586-019-1333-x. PubMed DOI

Kimel A., Zvezdin A., Sharma S., Shallcross S., De Sousa N., García-Martín A., Salvan G., Hamrle J., Stejskal O., McCord J.. et al. The 2022 magneto-optics roadmap. J. Phys. D. 2022;55:463003. doi: 10.1088/1361-6463/ac8da0. DOI

Matsukura F., Tokura Y., Ohno H.. Control of magnetism by electric fields. Nat. Nanotechnol. 2015;10:209–220. doi: 10.1038/nnano.2015.22. PubMed DOI

Lei N., Devolder T., Agnus G., Aubert P., Daniel L., Kim J.-V., Zhao W., Trypiniotis T., Cowburn R. P., Chappert C., Ravelosona D., Lecoeur P.. Strain-controlled magnetic domain wall propagation in hybrid piezoelectric/ferromagnetic structures. Nat. Commun. 2013;4:1378. doi: 10.1038/ncomms2386. PubMed DOI PMC

Li D., Li S., Zhong C., He J.. Tuning magnetism at the two-dimensional limit: a theoretical perspective. Nanoscale. 2021;13:19812–19827. doi: 10.1039/D1NR06835K. PubMed DOI

Shokeen V., Sanchez Piaia M., Bigot J. Y., Müller T., Elliott P., Dewhurst J. K., Sharma S., Gross E. K. U.. Spin Flips versus Spin Transport in Nonthermal Electrons Excited by Ultrashort Optical Pulses in Transition Metals. Phys. Rev. Lett. 2017;119:107203. doi: 10.1103/PhysRevLett.119.107203. PubMed DOI

Chen J., Bovensiepen U., Eschenlohr A., Müller T., Elliott P., Gross E. K. U., Dewhurst J. K., Sharma S.. Competing Spin Transfer and Dissipation at Co/Cu(001) Interfaces on Femtosecond Timescales. Phys. Rev. Lett. 2019;122:067202. doi: 10.1103/PhysRevLett.122.067202. PubMed DOI

Hofherr M., Häuser S., Dewhurst J. K., Tengdin P., Sakshath S., Nembach H. T., Weber S. T., Shaw J. M., Silva T. J., Kapteyn H. C., Cinchetti M., Rethfeld B., Murnane M. M., Steil D., Stadtmüller B., Sharma S., Aeschlimann M., Mathias S.. Ultrafast optically induced spin transfer in ferromagnetic alloys. Sci. Adv. 2020;6:eaay8717. doi: 10.1126/sciadv.aay8717. PubMed DOI PMC

Scheid P., Sharma S., Malinowski G., Mangin S., Lebègue S.. Ab initio study of helicity-dependent light-induced demagnetization: from the optical regime to the extreme ultraviolet regime. Nano Lett. 2021;21:1943–1947. doi: 10.1021/acs.nanolett.0c04166. PubMed DOI

Dewhurst J. K., Elliott P., Shallcross S., Gross E. K. U., Sharma S.. Laser-induced intersite spin transfer. Nano Lett. 2018;18:1842–1848. doi: 10.1021/acs.nanolett.7b05118. PubMed DOI

He J., Li S., Frauenheim T., Zhou Z.. Ultrafast Laser Pulse Induced Transient Ferrimagnetic State and Spin Relaxation Dynamics in Two-Dimensional Antiferromagnets. Nano Lett. 2023;23:8348–8354. doi: 10.1021/acs.nanolett.3c02727. PubMed DOI PMC

Li S., Zhou L., Frauenheim T., He J.. Light-Controlled Ultrafast Magnetic State Transition in Antiferromagnetic–Ferromagnetic van der Waals Heterostructures. J. Phys. Chem. Lett. 2022;13:6223–6229. doi: 10.1021/acs.jpclett.2c01476. PubMed DOI

He J., Li S., Bandyopadhyay A., Frauenheim T.. Unravelling Photoinduced Interlayer Spin Transfer Dynamics in Two-Dimensional Nonmagnetic-Ferromagnetic van der Waals Heterostructures. Nano Lett. 2021;21:3237–3244. doi: 10.1021/acs.nanolett.1c00520. PubMed DOI

Zhou Z., Li M., Frauenheim T., He J.. Controlling Ultrafast Magnetization Dynamics via Coherent Phonon Excitation in a Ferromagnet Monolayer. Nano Lett. 2024;24:12062–12069. doi: 10.1021/acs.nanolett.4c02325. PubMed DOI PMC

Hui D., Alqattan H., Zhang S., Pervak V., Chowdhury E., Hassan M. T.. Ultrafast optical switching and data encoding on synthesized light fields. Sci. Adv. 2023;9:eadf1015. doi: 10.1126/sciadv.adf1015. PubMed DOI PMC

Wu N., Zhang S., Chen D., Wang Y., Meng S.. Three-stage ultrafast demagnetization dynamics in a monolayer ferromagnet. Nat. Commun. 2024;15:2804. doi: 10.1038/s41467-024-47128-4. PubMed DOI PMC

Beaurepaire E., Merle J. C., Daunois A., Bigot J. Y.. Ultrafast Spin Dynamics in Ferromagnetic Nickel. Phys. Rev. Lett. 1996;76:4250–4253. doi: 10.1103/PhysRevLett.76.4250. PubMed DOI

Thiele J.-U., Buess M., Back C. H.. Spin dynamics of the antiferromagnetic-to-ferromagnetic phase transition in FeRh on a sub-picosecond time scale. Appl. Phys. Lett. 2004;85:2857–2859. doi: 10.1063/1.1799244. DOI

Gorkan T., Das J., Kapeghian J., Akram M., Barth J. V., Tongay S., Akturk E., Erten O., Botana A. S.. Skyrmion formation in Ni-based Janus dihalide monolayers: Interplay between magnetic frustration and Dzyaloshinskii-Moriya interaction. Phys. Rev. Mater. 2023;7:054006. doi: 10.1103/PhysRevMaterials.7.054006. DOI

Guo S.-D., Zhu Y.-T., Qin K., Ang Y.-S.. Large out-of-plane piezoelectric response in ferromagnetic monolayer NiClI. Appl. Phys. Lett. 2022;120:232403. doi: 10.1063/5.0095917. DOI

Kresse G., Hafner J.. Ab initio. Phys. Rev. B. 1993;47:558–561. doi: 10.1103/PhysRevB.47.558. PubMed DOI

Kresse G., Joubert D.. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B. 1999;59:1758–1775. doi: 10.1103/PhysRevB.59.1758. DOI

Perdew J. P., Burke K., Ernzerhof M.. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996;77:3865–3868. doi: 10.1103/PhysRevLett.77.3865. PubMed DOI

Dudarev S. L., Botton G. A., Savrasov S. Y., Humphreys C. J., Sutton A. P.. Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U study. Phys. Rev. B. 1998;57:1505–1509. doi: 10.1103/PhysRevB.57.1505. DOI

Dewhurst, J. K. ; Sharma, S. ; et al. The ELK code. http://elk.sourceforge.net, January 14, 2018.

Von Barth U., Hedin L.. A local exchange-correlation potential for the spin polarized case. i. J. Phys. C: Solid State Phys. 1972;5:1629. doi: 10.1088/0022-3719/5/13/012. DOI