The control of antiferromagnets with ultrashort optical pulses has emerged as a prominent field of research. Tailored laser excitation can launch coherent spin waves at terahertz frequencies, yet a comprehensive description of their generation mechanisms is still lacking despite extensive efforts. Using terahertz emission spectroscopy, we investigate the generation of a coherent magnon mode in the van der Waals antiferromagnet NiPS_{3} under a range of photoexcitation conditions. By tuning the pump photon energy from transparency to resonant with a d-d transition, we reveal a striking change in the coherent magnon's dependence on the pump polarization, indicating two distinct excitation mechanisms. Our findings provide a strategy for the manipulation of magnetic modes via photoexcitation around subgap electronic states.
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http://dx.doi.org/10.1103/PhysRevLett.134.066903 | DOI Listing |
Terahertz (THz) waves, a novel type of radiation with quantum and electronic properties, have attracted increasing attention for their effects on the nervous system. Spatial working memory, a critical component of higher cognitive function, is coordinated by brain regions such as the infralimbic cortex (IL) region of the medial prefrontal cortex and the ventral cornu ammonis 1 (vCA1) of hippocampus. However, the regulatory effects of THz waves on spatial working memory and the underlying mechanisms remain unclear.
View Article and Find Full Text PDFPhys Chem Chem Phys
March 2025
Department of Chemistry, Lehigh University, 6 E. Packer Ave., Bethlehem, Pennsylvania 18015, USA.
Despite their wide use as molecular photoswitches, the mechanistic photophysics of azo dyes are complex and nuanced, and therefore under-explored. To understand the complex electronic interactions that govern the photoisomerization and thermal reversion of two phenyl-azo-indole dyes that differ by R-sterics near the azo bond, potential energy surfaces that combine the dihedral rotation of the azo bond and the aryl inversion on each side of the azo bond were calculated with density functional theory and time-dependent density functional theory. These multidimensional singlet surfaces provide insights into the correlated rotation and inversion pathways allowing for detailed understanding of both photoisomerization, governed by the excited-state surfaces, and thermal reversion, governed by the ground-state surface, mechanisms to be developed.
View Article and Find Full Text PDFOrthop Surg
March 2025
Department of Orthopaedic Surgery and Orthopaedic Research Institute, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China.
Recent literature has increasingly demonstrated the significant function of autonomic nerves in regulating physiological and pathological changes associated with the skeletal system. Extensive studies have been conducted to understand the contribution of the autonomic nervous system (ANS) to skeletal metabolic homeostasis and resistance to aseptic inflammation, specifically from the viewpoint of skeletal neurobiology. There have been plenty of studies on how the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS), the two main branches of the ANS, regulate bone remodeling, which is the process of bone formation and resorption.
View Article and Find Full Text PDFCurrently, static fluorescent anti-counterfeiting technology struggles to cope with the increasingly sophisticated counterfeiting techniques, making the dynamic multimode regulation scheme an urgent necessity. Herein, Sm3+ mono-/co-doped LiTaO3 (LTO) phosphors are prepared by high temperature solid state method. Under 254 nm excitation, the emission chromaticity of LTO: Tb3+, Sm3+ is modulated from green to yellow by increasing Sm3+ content due to Tb3+ → Sm3+ energy transfer.
View Article and Find Full Text PDFBrain
March 2025
School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, often present with severe psychiatric symptoms, yet the neuropathological mechanisms underlying their cognitive deficits remain insufficiently understood. In this study, we constructed an animal model using anti-NMDAR IgG purified from the serum of patients with anti-NMDAR encephalitis, and we used IgG obtained from healthy individuals as a control. Daily administration of anti-NMDAR IgG into the medial prefrontal cortex (mPFC) of mice for 7 days resulted in cognitive impairments resembling clinical symptoms, which spontaneously resolved 30 days after discontinuing the injections.
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