2021/04/18 by Romakanta Bhattarai, Xiao Shen · 8 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #Anisotropy #Density functional theory #Dielectric #Dielectric function #Electronic structure #Hybrid functional #Perturbation theory (quantum mechanics) #Phase-change materials and chalcogenides #Raman spectroscopy #Semiconductor materials and interfaces #cond-mat.mtrl-sci
paper · pdf · doi:10.1063/5.0054391
published in Journal of Applied Physics 129(22) (American Institute of Physics)
arxiv created 2021/04/18 · openalex created_date 2021/04/26 · openalex publication_date 2021/06/10 · arxiv updated 2021/06/30 · openalex updated_date 2026/08/06
The optical and electronic properties of α-SiTe, β-SiTe, and RX-SiTe2 are investigated. A detailed analysis of electronic properties is done using standard density functional theory (DFT) and hybrid functional methods. The static dielectric properties are investigated using the density functional perturbation theory method. The optical properties are studied under three different methods: standard DFT, many-body Green's functions, and the Bethe–Salpeter equation. Our calculations show that the SiTe compounds possess extremely high static dielectric constants in their bulk forms [ε0(⊥) = 68.58 and ε0(‖) = 127.29 for α-SiTe, and ε0(⊥) = 76.23 and ε0(‖) = 74.61 for β-SiTe]. The frequency-dependent dielectric functions Im(ε) have very large values (>100) in the optical regime, which are among the highest of layered materials, suggesting them as excellent light absorbents in the corresponding frequencies. α-SiTe exhibits a high degree of optical anisotropy as compared to the other two compounds, consistent with their structural configurations. A strong interlayer excitonic effect is observed in bulk RX-SiTe2. In addition, an analysis of Raman intensity is also performed.