First principle calculations: The electronic, optical, mechanical, and vibrational properties of TiS3

The computational predictions of transition-metal tri-chalcogenide (TMTCs) were performed using ab initio density functional theory (DFT) to investigate the electronic band structure, the partial density of states (PDOS), optical absorptions, dielectric functions, complex conductivity, reflectivity, refractive index, electron loss, the Poisson’s ratio, Young’s modulus, bulk-to-shear ratio, and phonon dispersion. The bandgap is measured from the valence band maximum (VBM) to the conduction band minimum (CBM) with the G–Z transitions. This suggests that the material is an indirect bandgap semiconductor. The electronic bandgap ([Formula: see text] is significantly improved with nonlocal hybrid functionals, especially in HSE0s, with [Formula: see text] of 1.0[Formula: see text]eV, which is in excellent agreement with the experimental data. However, our data shows that the HF-LDA exchange correlations significantly overestimate the [Formula: see text] with 7.33[Formula: see text]eV. Also, our optical absorption data indicates a high absorption coefficient of about [Formula: see text][Formula: see text]cm[Formula: see text]. The absorption peak of 7.4[Formula: see text]eV indicates TiS 3 can be applied in vacuum ultra-violet (VUV) applications. The reflectivity is also shown to be high, with over 90% of light being reflected. The mechanical stability of the monoclinic system can be testified by our elastic coefficients and the phonon dispersions.