The anharmonic properties of the longitudinal optical (LO) phonon mode of Mg-doped ZnS (Zn MgS) are investigated using the Balkanski and Klemens models on the temperature-dependent Raman spectra. The variation in the position of the Raman line, peak width, and phonon lifetime with temperature was fitted using three and four phonon decay mechanisms. The values of the anharmonic fitting parameters indicated low anharmonicity. A lifetime of ∼0.17 ps at 90 K indicated a fast phonon decay. In addition, the thin film is analyzed to evaluate its surface characteristics using Raman mapping that showed chemical homogeneity over a large area of the film. Furthermore, we analyzed spatial variations of Raman line intensity, peak area, linewidth, and line position of the LO phonon mode. Raman analysis helped in understanding the phonon-phonon interaction mechanism in Zn MgS thin films.
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http://dx.doi.org/10.1063/5.0097992 | DOI Listing |
ACS Nano
March 2025
State Key Laboratory of Radio Frequency Heterogeneous Integration, Institute of Microscale Optoelectronics, College of Electronics and Information Engineering, Shenzhen University, Shenzhen 518060, China.
The development of acoustic nanocavities with resonant frequencies in the gigahertz to terahertz range has enabled advancements in quantum information processing, acoustic sensing, and advanced optoacoustic devices. Here, we demonstrate the generation and strong coupling of coherent acoustic phonons within metal-van der Waals (vdWs) heterostructure nanocavities, constructed from semiconductor MoS and insulating h-BN thin films, integrated with chemically synthesized Au nanosheets. Both heterostructures exhibit extended coherent phonon spectra, as observed through ultrafast femtosecond pump-probe spectroscopy.
View Article and Find Full Text PDFPhys Rev Lett
February 2025
Rutgers University, Center for Materials Theory, Department of Physics and Astronomy, Piscataway, New Jersey 08854, USA.
We show that driving optical phonons above a threshold fluence induces spatiotemporal orders, where material properties oscillate at an incommensurate wave vector q_{0} in space and at half the drive frequency in time. The order is robust against temperature on timescales much larger than the lifetime of the excited modes and can be accompanied by a static 2q_{0} modulation. We make predictions for time-resolved diffraction and provide estimates for candidate materials.
View Article and Find Full Text PDFDalton Trans
February 2025
LEEP Device Research Group, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India - 603203.
Owing to their superior optoelectronic properties, lead-free halide double perovskites (HDPs) have been extensively studied for a wide range of optoelectronic applications, especially for fabricating white light-emitting diodes (WLEDs). Considering white light emission, the HDP structure's dual octahedral configuration facilitates greater lattice distortion, thereby fostering strong electron-phonon coupling-derived self-trapped exciton (STE) emission upon photoexcitation. Herein, we propose facile fabrication of a highly feasible phosphor-converted white light LED and an intensive analysis of the structural, compositional and photophysical properties of a tri-cation mixed halide double perovskite.
View Article and Find Full Text PDFNanoscale
February 2025
Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.
In addition to its excellent photoelectronic properties, the CsPbBr perovskite has been reported as a low thermal conductivity () material. However, few studies investigated the microscopic mechanisms underlying its low . Studying its thermal transport behavior is crucial for understanding its thermal properties and thus improving its thermal stability.
View Article and Find Full Text PDFNanoscale
February 2025
Metallurgical and Materials Engineering Department, Indian Institute of Technology Kharagpur, India.
Effective thermal management is essential for maintaining the operational stability and data security of magnetic devices across diverse fields, including thermoelectric, sensing, data storage, and spintronics. In this study, density functional theory calculations were conducted to explore the spin-induced modifications in the phonon-mediated thermal properties of H-phase monolayer VS, a two-dimensional (2D) ferromagnet. Our investigation revealed that the 2D H-phase of VS exhibits a substantial thermal switching ratio, exceeding four at the Curie temperature, due to the coupling between magnetic order and lattice vibrations.
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