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Antiferromagnets (AFMs) are more advantageous in realizing ultrafast spin-based processes, but remain challenging to manipulate. The lack of proper knobs in AFM-based ultrafast devices greatly hampers their applications. Here, we innovate an antiferromagnet/topological insulator (AFM/TI) heterostructure MnSe/(Bi,Sb)Te to realize laser-induced transient magnetic moment, and further demonstrate optically controllable circularly polarized ultrafast terahertz (THz) pulse generation, under zero external magnetic field. Intriguingly, we find two mechanisms underlying the ultrafast THz pulse generation: direct magnetic dipole radiation and spin-charge conversion resulted electric dipole radiation. Our findings provide a suitable platform for efficient and polarization-controllable ultrafast THz devices via optical means.
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http://dx.doi.org/10.1038/s41467-025-60060-5 | DOI Listing |
Phys Rev Lett
August 2025
University of Delaware, Department of Physics and Astronomy, Newark, Delaware 19716, USA.
Ultrafast light-driven strongly correlated antiferromagnetic insulators, such as prototypical NiO with a large Mott energy gap ≃4 eV, have recently attracted experimental attention using photons of both subgap [H. Qiu et al., Nat.
View Article and Find Full Text PDFNano Lett
September 2025
Department of Physics, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
On-chip terahertz (THz) spectroscopy has attracted growing attention because of its capability of measuring samples far smaller than the Rayleigh diffraction limit. The technique also allows the investigation of nonlinear responses of materials, which is indispensable for the development of ultrafast devices operating with a THz bandwidth. Here, we report the development of an on-chip THz-pump THz-probe spectroscopy technique that enables the study of ultrafast electrical-pulse-induced nonequilibrium phenomena.
View Article and Find Full Text PDFClin Exp Nephrol
September 2025
Department of Medical Science and Cardiorenal Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan.
Background: Sacubitril/valsartan is typically prescribed for patients with heart failure and hypertension. We previously reported that sacubitril/valsartan provides comparable blood pressure (BP) reduction and superior tolerability compared to thiazide diuretics. This post hoc study aimed to compare the effects of sacubitril/valsartan and thiazide diuretics in patients with chronic kidney disease (CKD).
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
Lehrstuhl für Theoretische Chemie II, Ruhr-Universität Bochum, 44780 Bochum, Germany.
Ultrafast, time-resolved spectroscopies enable the direct observation of molecular dynamics in condensed-phase systems and have revealed key insights into energy transport, hydrogen-bond dynamics, and vibrational coupling. While ab initio molecular dynamics (AIMD) provides accurate, atomistic resolution of such dynamics, it becomes prohibitively expensive for non-equilibrium processes that require many independent trajectories to capture the stochastic nature of excitation and relaxation. To address this, we implemented a machine learning potential that incorporates time-dependent electric fields in a perturbative fashion, retaining AIMD-level accuracy.
View Article and Find Full Text PDFACS Photonics
August 2025
Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, U.K.
Generation of broadband terahertz (THz) pulses with variable polarization and carrier-envelope phase can enable the tailoring of THz beam wavefronts for advanced applications in THz imaging and spectroscopy and for strong THz field optics. While metasurfaces composed of deeply subwavelength THz emitters have recently been demonstrated to define the polarization and spatial profile of the generated THz fields, precise phase control or synthesis of THz pulse waveforms remains a challenging problem. Here, we propose and demonstrate metasurfaces composed of indium arsenide (InAs) nanoscale ribbon arrays capable of generating THz pulses with variable carrier-envelope phase.
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