Observation of Fano resonances in various physical phenomena is usually ascribed to the coupling of discrete states with background continuum, as it has already been reported for various physical phenomena. Here, we report on Fano lineshapes of nonthermal GHz phonons generated and observed with pumped Brillouin light scattering in gold-silicon thin membranes, overlapping the broad zero-shift background of yet questionable origin. The system's broken mid-plane symmetry enabled the generation of coherent quasi-symmetric and quasi-antisymmetric Lamb acoustic waves/phonons, leading to the four orders-of-magnitude enhancement of Brillouin light scattering. Notably, the membrane asymmetry resulted also in the mode-dependent Stokes and anti-Stokes Fano lineshapes asymmetry.
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http://dx.doi.org/10.1016/j.pacs.2023.100478 | DOI Listing |
J Phys Chem Lett
January 2025
Institute of Bioproducts and Paper Technology, Graz University of Technologyy, Inffeldgasse 23, 8010 Graz, Austria.
The mechanical properties of metal-organic frameworks (MOFs) are of high fundamental and practical relevance. A particularly intriguing technique for determining anisotropic elastic tensors is Brillouin scattering, which so far has rarely been used for highly complex materials like MOFs. In the present contribution, we apply this technique to study a newly synthesized MOF-type material, referred to as GUT2.
View Article and Find Full Text PDFUsing the first principle calculations, we propose a boron and nitrogen cluster incorporated graphene system for efficient valley polarization. The broken spatial inversion symmetry results in high Berry curvature at and valleys of the hexagonal Brillouin zone in this semiconducting system. The consideration of excitonic quasiparticles within the approximation along with their scattering processes using the many-body Bethe-Salpeter equation gives rise to an optical gap of 1.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Physics, Florida State University, 612 Keen Building, Florida State University, Tallahassee, Florida, 32306, UNITED STATES.
We argue that alternating-layer structures of lattice mismatched or misaligned (twisted) atomically-thin layers should be expected to be more efficient absorbers of the broad-spectrum of solar radiation than the bulk material of each individual layer. In such mismatched layer-structures the conduction and valence bands of the bulk material, split into multiple minibands separated by minigaps confined to a small-size emerging Brillouin zone due to band-folding. We extended the Shockley-Queisser approach to calculate the photovoltaic efficiency for a band split into minibands of bandwidth $\Delta E$ and mini-gaps $\delta G$ to model the case when such structures are used as solar cells.
View Article and Find Full Text PDFSci Rep
January 2025
ISQI, Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań, Poland.
High-resolution Brillouin spectroscopy was employed to investigate the anisotropy in surface wave velocities within a bulk single crystal of SbTe, a well-known layered van der Waals material. By leveraging the bulk elastic constants derived from various simulation methods, we were able to theoretically calculate the distribution of surface acoustic phonon velocities on the cleavage plane of the material. Upon analyzing multiple simulation results, it became evident that the most significant discrepancies arose in the calculations of the elastic constant c, with values ranging from 48 to 98 GPa.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, University of California, Davis, 1 Shields Avenue, Davis, California 95616, United States.
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