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Research output: Contribution to Journal/Magazine › Letter › peer-review
Research output: Contribution to Journal/Magazine › Letter › peer-review
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TY - JOUR
T1 - Temporal and spectral fingerprint of ultrafast all-coherent spin switching
AU - Schlauderer, S.
AU - Lange, C.
AU - Baierl, S.
AU - Ebnet, T.
AU - Schmid, C. P.
AU - Valovcin, D. C.
AU - Zvezdin, A. K.
AU - Kimel, A.V.
AU - Mikhaylovskiy, Rostislav
AU - Huber, R.
PY - 2019/5/15
Y1 - 2019/5/15
N2 - Future information technology demands ultimately fast, low-loss quantum control. Intense light fields have facilitated important milestones, such as inducing novel states of matter, accelerating electrons ballistically, or coherently flipping the valley pseudospin. These dynamics leave unique signatures, such as characteristic bandgaps or high-order harmonic radiation. The fastest and least dissipative way of switching the technologically most important quantum attribute – the spin – between two states separated by a potential barrier is to trigger an all-coherent precession. Pioneering experiments and theory with picosecond electric and magnetic fields have suggested this possibility, yet observing the actual dynamics has remained out of reach. Here, we show that terahertz (1 THz = 1012 Hz) electromagnetic pulses allow coherent navigation of spins over a potential barrier and we reveal the corresponding temporal and spectral fingerprints. This goal is achieved by coupling spins in antiferromagnetic TmFeO3 with the locally enhanced THz electric field of custom-tailored antennas. Within their duration of 1 ps, the intense THz pulses abruptly change the magnetic anisotropy and trigger a large-amplitude ballistic spin motion. A characteristic phase flip, an asymmetric splitting of the magnon resonance, and a long-lived offset of the Faraday signal are hallmarks of coherent spin switching into adjacent potential minima, in agreement with a numerical simulation. The switchable spin states can be selected by an external magnetic bias. The low dissipation and the antenna’s sub-wavelength spatial definition could facilitate scalable spin devices opera¬ting at THz rates.
AB - Future information technology demands ultimately fast, low-loss quantum control. Intense light fields have facilitated important milestones, such as inducing novel states of matter, accelerating electrons ballistically, or coherently flipping the valley pseudospin. These dynamics leave unique signatures, such as characteristic bandgaps or high-order harmonic radiation. The fastest and least dissipative way of switching the technologically most important quantum attribute – the spin – between two states separated by a potential barrier is to trigger an all-coherent precession. Pioneering experiments and theory with picosecond electric and magnetic fields have suggested this possibility, yet observing the actual dynamics has remained out of reach. Here, we show that terahertz (1 THz = 1012 Hz) electromagnetic pulses allow coherent navigation of spins over a potential barrier and we reveal the corresponding temporal and spectral fingerprints. This goal is achieved by coupling spins in antiferromagnetic TmFeO3 with the locally enhanced THz electric field of custom-tailored antennas. Within their duration of 1 ps, the intense THz pulses abruptly change the magnetic anisotropy and trigger a large-amplitude ballistic spin motion. A characteristic phase flip, an asymmetric splitting of the magnon resonance, and a long-lived offset of the Faraday signal are hallmarks of coherent spin switching into adjacent potential minima, in agreement with a numerical simulation. The switchable spin states can be selected by an external magnetic bias. The low dissipation and the antenna’s sub-wavelength spatial definition could facilitate scalable spin devices opera¬ting at THz rates.
KW - Terahertz
KW - Magnetism
KW - Ultrafast phenomena
KW - Magneto-Optic
U2 - 10.1038/s41586-019-1174-7
DO - 10.1038/s41586-019-1174-7
M3 - Letter
VL - 569
SP - 383
EP - 387
JO - Nature
JF - Nature
SN - 0028-0836
ER -