Raman Tensor of Layered Td-WTe₂

Abstract

Weyl semimetal Td-WTe 2 has attracted extensive attention due to its abundant physical properties. Further study on Td-WTe 2 crystal structure is helpful for its understanding and modification in application. In this article, a method for studying crystal symmetry based on Raman tensor is proposed. Specifically, it analyzed the anisotropy of the material structure by the angle-resolved polarized Raman spectroscopy and discussed the Raman selection rules and the physical image of the Raman tensor matrix element in depth, which filled in the deficiency of information on Raman tensor elements obtained simply by experiments. According to the study and discussion, the basal and cross plane of Td-WTe 2 crystal show incompletely consistent polarization dependence of Raman scattering intensity. Combined with theoretical calculations and angle-resolved Raman spectrum experiments, the corresponding Raman tensor elements of each vibration mode are obtained. The dominant vibration orientation of each mode depends on the differential polarizability corresponding to the Raman tensor element. For the comparison of shrinkage degrees, the mode with larger shrinkage degree tends to vibrate along the c-axis. The results provide a new way for studying the Raman tensor of other transition metal chalcogenides and offers a noble direction for the application of anisotropic thin materials.

Flexible Memory Device Composed of Metal-Oxide and Two-Dimensional Material (SnO2/WTe2) Exhibiting Stable Resistive Switching

“…The quality of the 2D WTe2 film was verified under Raman spectroscopy analysis and the X-ray photoelectronic spectroscopy (XPS) spectra. In Raman analysis of the WTe2 films on the flexible PET substrate, the four prominent peaks, which appear because of in-plane and out-of-plane modes of vibration [23,24], were observed around 110, 142.1, 168.1, and 222 cm −1 , as shown in Figure 2a. Furthermore, the surface analysis of the synthesized WTe2 films was investigated under the XPS to observe the chemical surface states, as illustrated in Figure 2b.…”

Laser tuning in AlN single crystals

“…The measurement geometry is shown in Fig. 1a [24][25][26][27][28][29][30][31][32][33][34], where a polarizer with fixed polarization direction was placed in the collecting optical path to ensure that the polarization direction of scattering light was strictly consistent with that of pump light. In order to avoid the influences of pump light absorption and resonance Raman scattering on the intensity of scattering light, 488-nm Ar+ gas laser was used as pump light and focused on the AlN surface through a 50× quartz lens [35][36][37][38][39].…”

Quantum Ensembles of Silicon Nanoparticles: Discrimination of Static and Dynamic Photoluminescence Quenching Processes

“…68 A typical application involves conjugation of an organic dye molecule to an emissive semiconductor quantum dot. 69 The two distinct emissions are influenced separately by the analyte, enabling the ratiometric measurement. Researchers have shown that a heterogeneous mixture of quantum dots of different sizes (and hence different spectral characteristics) can be used for ratiometric sensing, 70,71 although for many applications the nonuniform size distribution substantially complicates the interpretation of such data.…”