Infrared reflectance spectrum of BN calculated from first principles

• Published in: Solid state communications 2007-02, Vol.141 (5), p.262-266
• Main Authors: Cai, Yongqing, Zhang, Litong, Zeng, Qingfeng, Cheng, Laifei, Xu, Yongdong
• Format: Article
• Language: English
• Subjects: A. BN; C. Infrared reflectance spectrum; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; E. First principles; Exact sciences and technology; Lattice dynamics; Permittivity (dielectric function); Phonon states and bands, normal modes, and phonon dispersion; Phonons and vibrations in crystal lattices; Physics
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2006.10.040

Using the linear response theory, vibrational and dielectric properties are calculated for c -BN, w -BN and h -BN. Calculations of the zone-center optical-mode frequencies (including LO–TO splittings) are reported. All optic modes are identified and excellent agreement is found between the theory and experimental results. The static dielectric tensor is decomposed into contributions arising from individual infrared-active phonon modes. It is found that all the structures have a smaller lattice dielectric constants than those of the electronic contributions. Finally, the infrared reflectance spectrums are presented. Our theoretical results indicate that w -BN shows a similar reflectivity spectrum as c -BN. It is difficult to tell apart the wurtzite structure from the zinc blende phase by IR spectroscopy.