جستجوی مقالات مرتبط با کلیدواژه « SrTiO3 » در نشریات گروه « فیزیک »

The electronic properties of thin films and nanostructures as well as the surface electronic structure can be obtained using Reflection electron energy loss technique at low energy. In this work, dielectric function of SrTiO3 is obtained by Yubero-Tougaard method using the experimental inelastic cross section obtained by Tougaard-Chorkrndorf method. Theoretical cross section obtained at energy 1423 eV, incidence angle 15 and exit angle 35 was found to be in good consistence with experimental cross section. In addition, the angular distribution of surface excitation parameter for this crystal was determined at energies 1000, 1423, 2000, 2500 and 3000 eV. To this end, the definition presented by Pauly and Tougaard was used which relies on the variation in excitation probability at surface and moving in semi-infinite medium. This parameter was calculated based on the differential inelastic electron dispersion cross section using QUEELS software which is valid for reflection electron energy loss spectrum.

In this study, optical properties of BaTiO3/SrTiO3/CaTiO3 compounds such as reflective index, extinction coefficient, absorption coefficient, reflectivity, energy loss spectrum and optical conductivity have been calculated and investigated in their stable phases, rhombohedral/ cubic/ orthohorombic phase with p4mm/m3m/pbnm space group respectively. The calculations have been conducted with pseudo-potential by GGA approximation in the frame work of Density Functional Theory. The obtained results for constant lattice after optimization, static dielectric constant, reflective index and plasma frequency have good accord with the experimental results and other theoretic studies. With respect to these quantities, perovskite oxides are good dielectrics. With respect to dielectic constants, and suitable optical absorbtion in the range of 4-12 eV, these perovskite oxides are good dielectrics. These compounds are transparent in energies above 13eV,and the maximum amount of conductivity occurs within 5eV. Also D coefficient calculated by Gladstone-Dale equation.