A Comparative Study of Optical Anisotropies of BC₃ and B₃C Systems by Density Functional Theory

Abstract

The optical properties of (8,0) BC 3 and B 3 C single-wall carbon nanotubes (SWCNTs) are computed using ab initio density functional theory (DFT). The electronic band structure reveals that the Fermi energy of B 3 C system is reduced compared to BC 3 . The static dielectric constant in the long wavelength limit for B 3 C system is 9 times larger than that of BC 3 in unpolarized electromagnetic field. Within 10 eV frequency (energy) range, the absorption coefficient of B 3 C is higher compared to BC 3 , while, above 10 eV, it is less than that of BC 3 . In parallel polarization, the peak of the loss function for B 3 C is shifted to higher frequency (energy) region with significantly six orders of magnitude compared to BC 3 system. The analysis of this study indicates that the optical anisotropies can be gained easily in these boron-doped systems by appropriately choosing the direction of the polarization of the electromagnetic field. Besides, the results of the loss functions may throw some light on the nature of collective excitations of these two systems.

Specific features of electronic structures and optical susceptibilities of g-BC3 and t-BC3 phases

“…The region confined between 5.0-10.0 eV is considered as a lossless region. Fig.9(c) illustrates the loss function L(o) which confirms the existence of the lossless region between 5.0 eV and 10.0 eV in coincidence with our observation in Fig.9(a) and (b) and in agreement with previous work 36. The loss function's peaks represent the plasma frequencies (o P ).…”