A05 - Elementary terahertz spin interactions in magnetic solids
In this project, we plan to investigate the coupling of ordered spins in magnetic solids to the electronic and lattice degrees of freedom on the ultrafast time scales of elementary interaction processes. For this purpose, we will make use of a highly selective pump-probe technique with sub-picosecond time resolution: an electromagnetic pump pulse (with center frequency tunable from the terahertz (THz) to the ultraviolet spectral range) excites specific low-energy resonances (e.g. magnons, phonons, electron-hole pairs). The impact of this perturbation on other degrees of freedom is monitored by a subsequently arriving probe pulse that is sensitive to observables such as magnetization, electronic conductivity and phonon occupation. To reduce complexity of the dynamics triggered by the pump, we focus on insulators in which the electron-orbital degrees of freedom are frozen out at room temperature, but can selectively be excited by a suitable optical pump pulse.
Using this approach, we expect to gain new and specific insights into both spin-electron and spin-lattice interactions, a central goal of ultrafast magnetism research. Examples of the questions addressed are: how does magnetic order in a given material respond to selectively excited electron-hole pairs, crystal-field transitions, optical or acoustic phonons? How fast are energy and angular momentum transferred between spins and the other subsystems? What is the dominant spin coupling underlying these processes? How can we transiently modify properties of the material, in particular the strength with which spins couple to the other degrees of freedom?
To implement this project, a versatile THz pump-probe experiment will be set up, with challenging requirements in terms of THz pulse energy (>1 μJ), signal-to-noise ratio, widely tunable pump frequency (from THz to ultraviolet), variable sample temperature and access to different probing schemes (magnetooptical effects at optical and THz frequencies, incoherent Raman scattering and THz emission). Regarding materials, we will study electrically insulating model magnets, which are relevant for spintronics applications, but exhibit complementary
magnetic order: ferromagnetic EuO, antiferromagnetic NiO and ferrimagnetic yttrium iron garnet (YIG). Their orbital electronic degrees of freedom are frozen out at room temperature, but can selectively be excited by an optical pump pulse. Finally, we will apply our methodology to transition-metal dichalcogenides such as WSe2 to study transiently spin-polarized electrons following generation by a circularly polarized optical pump pulse.
Publications (2nd Funding Period 2022 - 2025)
- Distortion-free sampling of ultrabroadband terahertz electric fields by interfacial spin accumulation
A. L. Chekhov, Y. Behovits, J. J. F. Heitz, M.-A. Sysaki, S. Jaiswal, O. Gueckstock, B. R. Serrano, A. Ruge, J. Kredl, M. Wolf, M. Münzberg, G. Jakob, M. Kläui, T. S. Seifert, and T. Kampfrath
Sci. Adv. 11, eadq7741 (2025) - DOI: 10.1126/sciadv.adq7741
- Tunable ultrabroadband hybrid terahertz emitter combining a spintronic and a GaSe source
A. Alostaz, O. Gueckstock, J. Tong, J. Kredl, C. In, M. Münzenberg, C. M. Schneider, T. Kampfrath, and T. S. Seifert
Appl. Phys. Lett. 125, 212402 (2024) - DOI: 10.1063/5.0226564
- Radiation hardness of ultrabroadband spintronic terahertz emitters: En-route to a space-qualified terahertz time-domain gas spectrometer
O. Gueckstock, N. Stojanovic, Y. Ha, T. Hagelschuer, A. Denker, G. Kourkafas, T. S. Seifert, T. Kampfrath, and M. Gensch
Appl. Phys. Lett. 124, 141103 (2024) - DOI: 10.1063/5.0196951
- Accessing ultrafast spin-transport dynamics in copper using broadband terahertz spectroscopy
J. Jechumtál, R. Rouzegar, O. Gueckstock, C. Denker, W. Hoppe, Q. Remy, T. S. Seifert, P. Kubaščík, G. Woltersdorf, P. W. Brouwer, M. Münzenberg, T. Kampfrath, and L. Nádvorník
Phys. Rev. Lett. 132, 226703 (2024) - DOI: 10.1103/PhysRevLett.132.226703
- Optical damage thresholds of single-mode fiber-tip spintronic terahertz
emitters
F. Paries, F. Selz, C.N. Santos, J.-F. Lampin, P. Koleják, G. Lezier, D. Troadec, N. Tiercelin, M. Vanwolleghem, A. Addda, T. Krampfrath, T.S. Seifert, G. von Freymann, and D. Molter
Opt. Express 32, 14, 24826-24838 (2024) - DOI: 10.1364/OE.525747
- Terahertz spin-conductance spectroscopy: Probing coherent and incoherent ultrafast spin tunneling
R. Rouzegar, M. A. Wahada, A. L. Chekhov, W. Hoppe, G. Bierhance, J. Jechumtál, L. Nádvorník, M. Wolf, T. S. Seifert, S. S. P. Parkin, G. Woltersdorf, P. W. Brouwer, and T. Kampfrath
Nano Lett. 24, 7852 (2024) - DOI: 10.1021/acs.nanolett.4c00498
- Rotating spintronic terahertz emitter optimized for microjoule pump-pulse energies and megahertz repetition rates
A. Vaitsi, V. Sleziona, L.E. Parra López, Y. Behovits, F. Schulz, N. Martín Sabanés, T. Kampfrath, M. Wolf, T.S. Seifert, and M. Müller
Appl. Phys. Lett. 125, 071107 (2024) - DOI: 10.1063/5.0214469
- Terahertz Néel spin-orbit torques drive nonlinear magnon dynamics in antiferromagnetic Mn2Au
Y. Behovits, A. L. Chekhov, S. Yu. Bodnar, O. Gueckstock, S. Reimers, T. S. Seifert, M. Wolf, O. Gomonay, M. Kläui, M. Jourdan, and T. Kampfrath
Nat. Commun. 14, 6038 (2023) - DOI: 10.1038/s41467-023-41569-z
- Broadband spintronic detection of the absolute field strength of terahertz electromagnetic pulses
A. L. Chekhov, Y. Behovits, U. Martens, B. R. Serrano, M. Wolf, T. S. Seifert, M. Muenzenberg, and T. Kampfrath
Phys. Rev. Appl. 20, 034037 (2023) - DOI: 10.1103/PhysRevApplied.20.034037
- Shaping THz emission spectra by using sub-wavelength nanopatterned spintronic THz emitters
B. Das-Mohapatra, R. Rouzegar, E.Th. Papaioannou, T. Kampfrath, and G. Schmidt
arXiv:2308.07159 (2023) - DOI: 10.48550/arXiv.2308.07159
- Ultrafast and terahertz spintronics: Guest editorial
T. Kampfrath, A. Kirilyuk, S. Mangin, S. Sharma, and M. Weinelt
Appl. Phys. Lett. 123, 050401 (2023) - DOI:10.1063/5.0167151
- Emission of coherent THz magnons in an antiferromagnetic insulator triggered by ultrafast spin–phonon interactions
E. Rongione, O. Gueckstock, M. Mattern, O. Gomonay, H. Meer, C. Schmitt, R. Ramos, T. Kikkawa, M. Mičica, E. Saitoh, J. Sinova, H. Jaffrès, J. Mangeney, S. T. B. Goennenwein, S. Geprägs, T. Kampfrath, M. Kläui, M. Bargheer, T. S. Seifert, S. Dhillon, and R. Lebrun
Nat. Commun. 14, 1818 (2023) - DOI: 10.1038/s41467-023-37509-6
- Broadband spintronic terahertz source with peak electric fields exceeding 1.5 MV/cm
R. Rouzegar, A. L. Chekhov, Y. Behovits, B. R. Serrano, M. A. Syskaki, C. H. Lambert, D. Engel, U. Martens, M. Münzenberg, M. Wolf, G. Jakob, M. Kläui, T. S. Seifert, and T. Kampfrath
Phys. Rev. Appl. 19, 034018 (2023) - DOI: 10.1103/PhysRevApplied.19.034018 - Time-domain observation of ballistic orbital-angular-momentum currents with giant relaxation length in tungsten
T. S. Seifert, D. Go, H. Hayashi, R. Rouzegar, F. Freimuth, K. Ando, Y. Mokrousov, and T. Kampfrath
Nat. Nanotechnol. 18, 1132 (2023) - DOI: 10.1038/s41565-023-01470-8
- Spin-voltage-driven efficient terahertz spin currents from the magnetic Weyl semimetals Co2MnGa and Co2MnAl
G. Bierhance, A. Markou, O. Gueckstock, R. Rouzegar, Y. Behovits, A. L. Chekhov, M. Wolf, T. S. Seifert, C. Felser, and T. Kampfrath
Appl. Phys. Lett. 120, 082401 (2022) - DOI: 10.1063/5.0080308
- Impact of gigahertz and terahertz transport regimes on spin propagation and conversion in the antiferromagnet IrMn
O. Gueckstock, R. L. Seeger, T. S. Seifert, S. Auffret, S. Gambarelli, J. N. Kirchhof, K. I. Bolotin, V. Baltz, T. Kampfrath, and L. Nádvorník
Appl. Phys. Lett. 120, 062408 (2022) - DOI: 10.1063/5.0077868
- Terahertz-wave decoding of femtosecond extreme-ultraviolet light pulses
I. Ilyakov, N. Agarwal, J.-C. Deinert, J. Liu, A. Yaroslavtsev, L. Foglia, G. Kurdi, R. Mincigrucci, E. Principi, G. Jakob, M. Kläui, T. S. Seifert, T. Kampfrath, S. Kovalev, R. E. Carley, A. O. Scherz, and M. Gensch
Optica 9, 545 (2022) - DOI: 10.1364/OPTICA.453130
- Transition of laser-induced terahertz spin currents from torque- to conduction-electron-mediated transport
P. Jiménez-Cavero, O. Gueckstock, L. Nádvorník, I. Lucas, T.S. Seifert, M. Wolf, R. Rouzegar, P.W. Brouwer, S. Becker, G. Jakob, M. Kläui, C. Guo, C. Wan, X. Han, Z. Jin, H. Zhao, D. Wu, L. Morellón, and T. Kampfrath
Physical Review B 105, 184408 (2022) - DOI: 10.1103/PhysRevB.105.184408
- Terahertz spin-to-charge current conversion in stacks of ferromagnets and the transition-metal dichalcogenide NbSe2
L. Nádvorník, O. Gueckstock, L. Braun, C. Niu, J. Gräfe, G. Richter, G. Schütz, H. Takagi, M. Zeer, T. S. Seifert, P. Kubaščík, A. K. Pandeya, A. Anane, H. Yang, A. Bedoya-Pinto, S. S. P. Parkin, M. Wolf, Y. Mokrousov, H. Nakamura, and T. Kampfrath
Adv. Mater. Interfaces 9, 2201675 (2022) - DOI: 10.1002/admi.202201675
- Laser-induced terahertz spin transport in magnetic nanostructures arises from the same force as ultrafast demagnetization
R. Rouzegar, L. Brandt, L. Nádvorník, D. A. Reiss, A. L. Chekhov, O. Gueckstock, C. In, M. Wolf, T. S. Seifert, P. W. Brouwer, G. Woltersdorf, and T. Kampfrath
Phys. Rev. B 106, 144427 (2022) - DOI: 10.1103/PhysRevB.106.144427
- Spintronic sources of ultrashort terahertz pulses
T.S. Seifert, L. Chen, Z. Wei, T. Kampfrath, and J. Qi
Appl. Phys. Lett. 120, 180401 (2022) - DOI: 10.1063/5.0080357
- Average power scaling of THz spintronic emitters efficiently cooled in reflection geometry
T. Vogel, A. Omar, S. Mansourzadeh, F. Wulf, N. Martín Sabanés, M. Müller, T. S. Seifert, A. Weigel, G. Jakob, M. Kläui, I. Pupeza, T. Kampfrath, and C. J. Saraceno
Opt. Express 30, 20451 (2022) - DOI: 10.1364/OE.453539
Publications (1st Funding Period 2018 - 2021)
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Modulating the polarization of broadband terahertz pulses from a spintronic emitter at rates up to 10 kHz
O. Gueckstock, L. Nádvorník, T.S. Seifert, M. Borchert, G. Jakob, G. Schmidt, G. Woltersdorf, M. Kläui, M. Wolf, and T. Kampfrath
Optica 8, 1013 (2021) - DOI: 10.1364/OPTICA.430504
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Broadband terahertz probes of anisotropic magnetoresistance disentangle extrinsic and intrinsic contributions
L. Nadvorník, M. Borchert, L. Brandt, R. Schlitz, K. A. de Mare, K. Výborný, I. Mertig, G. Jakob, M. Kläui, S. T. B. Goennenwein, M. Wolf, G. Woltersdorf, and T. Kampfrath
Phys. Rev. X 11, 021030 (2021) - DOI: 10.1103/PhysRevX.11.021030
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Frequency-independent terahertz anomalous Hall effect in DyCo5, Co32Fe68 and Gd27Fe73 thin films from DC to 40 THz
T. S. Seifert, U. Martens, F. Radu, M. Ribow, M. Beritta, L. Nádvorník, R. Starke, T. Jungwirth, M. Wolf, I. Radu, M. Münzenberg, P. M. Oppeneer, G. Woltersdorf, and T. Kampfrath
Adv. Mater. 33, 2007398 (2021) - DOI: 10.1002/adma.202007398
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Terahertz spin-to-charge conversion by interfacial skew scattering in metallic bilayers
O. Gueckstock, L. Nádvorník, M. Gradhand, T. S. Seifert, G. Bierhance, R. Rouzegar, M. Wolf, M. Vafaee, J. Cramer, M. A. Syskaki, G. Woltersdorf, I. Mertig, G. Jakob, M. Kläui, and T. Kampfrath
Adv. Mater. 33, 2006281 (2021) - DOI: 10.1002/adma.202006281
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Ultrafast photocurrents in MoSe2 probed by terahertz spectroscopy
D. Yagodkin, L. Nádvornik, O. Gueckstock, C. Gahl, T. Kampfrath, and K. I. Bolotin
2D Mater. 8, 025012 (2021) - DOI: 10.1088/2053-1583/abd527
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High-throughput techniques for measuring the spin Hall effect
M. Meinert, B. Gliniors, O. Gueckstock, T. S. Seifert, L. Liensberger, M. Weiler, S. Wimmer, H. Ebert, and T. Kampfrath
Phys. Rev. Appl. 14, 064011 (2020) - DOI: 10.1103/PhysRevApplied.14.064011
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Spintronics with ultrashort terahertz pulses
T. Kampfrath, Section 13 in: The 2020 magnetism roadmap by E. Y. Vedmedenko, R. K. Kawakami, D. D. Sheka, P. Gambardella, A. Kirilyuk, A. Hirohata, C. Binek, O. Chubykalo-Fesenko, S. Sanvito, B. J. Kirby, J. Grollier, K. Everschor-Sitte, T. Kampfrath, C.-Y. You, and A. Berger
J. Phys. D: Appl. Phys. 53, 453001 (2020) - DOI: 10.1088/1361-6463/ab9d98
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Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers
T. Tanikawa, S. Karabekyan, S. Kovalev, S. Casalbuoni, V. Asgekar, S. Bonetti, S. Wall, T. Laarmann, D. Turchinovich, P. Zalden, T. Kampfrath, A. S. Fisher, N. Stojanovic, M. Gensch, and G. Geloni
J. Synchrotron Radiat. 27, 796 (2020) - DOI: 10.1107/S1600577520004245
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Dissecting spin-phonon equilibration in ferrimagnetic insulators by ultrafast lattice excitation
S. F. Maehrlein, I. Radu, P. Maldonado, A. Paarmann, M. Gensch, A. M. Kalashnikova, R. V. Pisarev, M. Wolf, P. M. Oppeneer, J. Barker, and T. Kampfrath
Sci. Adv. 4, eaar5164 (2018) - DOI: 10.1126/sciadv.aar5164
- Antiferromagnetic opto-spintronics
P. Němec, M. Fiebig, T. Kampfrath and A. V. Kimel
Nat. Phys. 14, 229 (2018) - DOI: 10.1038/s41567-018-0051-x