A combined experimental and first-principles study of tungsten ditelluride (WTe₂) Weyl semimetal structure and optical characteristics

In this study, we present a combined experimental and theoretical study of tungsten ditelluride (WTe₂), a Type-II Weyl semimetal transition-metal dichalcogenide. Single crystals of WTe₂ were synthesized using the chemical vapor transport method and then characterized using Raman, energy-dispersive X-ray spectroscopy and single-crystal XRD. Using density functional theory (DFT) and time-dependent DFT (TDDFT), we systematically explore the structural, electronic, and optical characteristics of WTe₂. Optimized lattice parameters and calculated band structures confirm the presence of characteristic Dirac and Weyl-like features, indicative of semi-metallic behavior. The dielectric function and optical absorption spectra computed via TDDFT reveal strong anisotropic responses, suggesting potential applications in optoelectronics and photonic devices. Similarly, the Dirac and Weyl-like behavior can be attributed to high harmonic generation. DFT and TDDFT results are compared with the literature which shows excellent agreement validating our computational approach. Our combined study provides a detailed understanding of the electronic structure and optical response of WTe₂, validating its classification as a type-II Weyl semimetal and highlighting its potential for optoelectronic, topological and high harmonic generation applications.