First-Principles Study of the Electronic, Optical Properties and Lattice Dynamics of Tantalum Oxynitride
First-principles calculations of the electronic, optical properties and lattice dynamics of tantalum oxynitride are performed with the density functional theory plane-wave pseudopotential method as implemented in the CASTEP code. The analysis of the electronic structure shows a covalent nature in Ta-N bonds and Ta-0 bonds. The hybridization of anion 2p and Ta 5d states results in enhanced dispersion of the valance band, raising the top of the valence band and leading to the visible-light response in TaON. It has high dielectric constant and the anisotropy is displayed obviously in the lower energy region. Our calculation indicated that TaON has excellent dielectric properties along 010 direction. Various optical properties, including the reflectivity, absorption coefficient, refractive index, and the energy-loss spectrum are derived from the complex dielectric function. We also present phonon dispersion relation, zone-center optical mode frequency, density of phonon states and some thermodynamic properties. The experimental IR modes (Bu at 808 cm-1 and Au at 863 cm-1) are well reproduced and assigned to a combination of stretching and bending vibration for Ta-N bond and Ta-O bond. The thermodynamic properties of TaON, such as heat capacity and Debye temperature, which were important parameters for the measurement of crystal physical properties, were first given for reference. Our investigations provide useful information for the potential application of this material.
Pan Li Weiliu Fan Yanlu Li Honggang Sun Xiufeng Cheng Xian Zhao Minhua Jiang
State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China Department of Ch
国际会议
武汉
英文
451-470
2010-09-01（万方平台首次上网日期，不代表论文的发表时间）