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Updated: Nov 3, 2025

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Temperature-Dependent Phonon Shifts in van der Waals Crystals
1State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials, Sun Yat-sen University, Guangzhou 510275, China.
Abstract:
In recent years, there has been an explosive increase in the research on van der Waals (vdW) crystals because of their great potential applications in many optoelectronic devices. It is necessary to determine their temperature-dependent lattice vibration characteristics because their thermal and electrical transport are closely related to the anharmonic phonon effect, which will affect the performance of the devices. We review the temperature-dependent Raman spectroscopy of vdW crystals, systematically introduce the thermal behavior of optical phonons, and summarize their shift with temperature. Upon analyzing the theoretical models and summarizing the reported experimental data, it is found that the phonon shifts of vdW crystals have a "quasi-linear" relationship with temperature, which is widely described with first-order temperature (FOT) coefficients obtained through a linear fit. Thus, subsequently, the phonon shifts of monolayer materials, different-thickness crystals, suspended and supported samples, in-plane and out-of-plane modes in the same vdW materials, as well as heterostructures and alloys are discussed through comparative analysis of FOT coefficients.
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