The optical properties of SrHfO3,were studied by first principle using the density functional theory.The dielectric functions and optical constants are calculated using the full potential–linearized augmented plane w...The optical properties of SrHfO3,were studied by first principle using the density functional theory.The dielectric functions and optical constants are calculated using the full potential–linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation(GGA)by Wien2k package. The theoretical calculated optical properties and energy loss(EEL)spectrum yield a static refractive index of1. 924and a Plasmon energy of 27eVfor cubic phase. The complex dielectric functions are calculated which are in good agreement with the available experimental results.展开更多
The electronic structure, energy band structure, total density of states (DOS) and electronic density of perovskite SrTiO3 in the cubic phase are calculated by the using full potential-linearized augmented plane wave ...The electronic structure, energy band structure, total density of states (DOS) and electronic density of perovskite SrTiO3 in the cubic phase are calculated by the using full potential-linearized augmented plane wave (FP-LAPW) method in the framework density functional theory (DFT) with the generalized gradient approximation (GGA) by WIEN2k package. The calculated band structure shows a direct band gap of 2.5 eV at the Γ point in the Brillouin zone.The total DOS is compared with experimental x-ray photoemission spectra. From the DOS analysis, as well as charge-density studies, I have conclude that the bonding between Sr and TiO2 is mainly ionic and that the TiO2 entities bond covalently.The calculated band structure and density of state of SrTiO3 are in good agreement with theoretical and experimental results.展开更多
The optical properties of CdBr2 were studied by first principle using the density functional theory. The dielectric functions and optical constants are calculated using the full potential-linearized augmented plane wa...The optical properties of CdBr2 were studied by first principle using the density functional theory. The dielectric functions and optical constants are calculated using the full potential-linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA). The theoretical calculated optical properties and energy Loss (EEL) spectrum yield a static refractive index of 2.1 and a plasmon energy of 13eV for hexagonal phase. The results, in comparison with the published data, are in good agreement with the experimental and previous theoretical results.展开更多
The optical properties of CdBr2 were studied by first principle using the density functional theory. The dielectric functions and optical constants are calculated using the full potential-linearized augmented plane wa...The optical properties of CdBr2 were studied by first principle using the density functional theory. The dielectric functions and optical constants are calculated using the full potential-linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA). The theoretical calculated optical properties and energy Loss (EEL) spectrum yield a static refractive index of 2.1 and a plasmon energy of 13eV for hexagonal phase. The results, in comparison with the published data, are in good agreement with the experimental and previous theoretical results.展开更多
The equilibrium crystal structure parameter and bulk modulus of the SrMoO3 perovskite has been calculated with ab-initio method based on density functional theory (DFT) using both local density approximation (LDA) and...The equilibrium crystal structure parameter and bulk modulus of the SrMoO3 perovskite has been calculated with ab-initio method based on density functional theory (DFT) using both local density approximation (LDA) and generalized gradient approximation (GGA). The corresponding total free energy along with its various components for SrMoO3 was obtained. The lattice parameter and bulk modulus calculated for SrMoO3 within LDA are 3.99 A and 143.025 GPa respectively whereas within GGA are 4.04 A and 146.14 GPa respectively, both agree well with the available experimental data. The total energy calculated within LDA and GGA is almost the same however lower results are obtained for GGA. All calculations have been carried out using ABINIT computer code.展开更多
First principles density functional theory calculations have been performed for the chemisorption of formate adsorption on some metal surfaces. For the most stable adsorption site of short-bridge, the calculated forma...First principles density functional theory calculations have been performed for the chemisorption of formate adsorption on some metal surfaces. For the most stable adsorption site of short-bridge, the calculated formate adsorption energy follows the order of Au(110) < Ag(110) < Cu(110) < Pd(110) < Pt(110) < Ni(110) < Rh(110) < Fe(100) < Mo(100), and a clear linear correlation exists between the adsorption energy and the corresponding heat of formation of metal oxides. Moreover, it has been found that the formate adsorption energy for the transition metals can be correlated well with its d-band center (εd), and the IB Group metals can be described by the coupling matrix element square (Vad2).展开更多
The electronic and optical properties of 2D Cu_2Si and Cu_2Si:Ti are investigated based on the density functional theory(DFT) using the FP-LAPW method and GGA approximation. The 2D Cu_2Si has metallic and non magnetic...The electronic and optical properties of 2D Cu_2Si and Cu_2Si:Ti are investigated based on the density functional theory(DFT) using the FP-LAPW method and GGA approximation. The 2D Cu_2Si has metallic and non magnetic properties, whereas adding Ti impurity to its structure changes the electronic behavior to the half-metallic with 3.256μB magnetic moment. The optical transition is not occurred in the infrared and visible area for the 2D Cu_2Si in x-direction and by adding Ti atom, the real part of dielectric function in the x-direction, Re(ε(ω))_x is reached to a Dirac peak at this energy range. Moreover, the absorption gap tends to zero in x-direction of the 2D Cu_2Si:Ti.展开更多
文摘The optical properties of SrHfO3,were studied by first principle using the density functional theory.The dielectric functions and optical constants are calculated using the full potential–linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation(GGA)by Wien2k package. The theoretical calculated optical properties and energy loss(EEL)spectrum yield a static refractive index of1. 924and a Plasmon energy of 27eVfor cubic phase. The complex dielectric functions are calculated which are in good agreement with the available experimental results.
文摘The electronic structure, energy band structure, total density of states (DOS) and electronic density of perovskite SrTiO3 in the cubic phase are calculated by the using full potential-linearized augmented plane wave (FP-LAPW) method in the framework density functional theory (DFT) with the generalized gradient approximation (GGA) by WIEN2k package. The calculated band structure shows a direct band gap of 2.5 eV at the Γ point in the Brillouin zone.The total DOS is compared with experimental x-ray photoemission spectra. From the DOS analysis, as well as charge-density studies, I have conclude that the bonding between Sr and TiO2 is mainly ionic and that the TiO2 entities bond covalently.The calculated band structure and density of state of SrTiO3 are in good agreement with theoretical and experimental results.
文摘The optical properties of CdBr2 were studied by first principle using the density functional theory. The dielectric functions and optical constants are calculated using the full potential-linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA). The theoretical calculated optical properties and energy Loss (EEL) spectrum yield a static refractive index of 2.1 and a plasmon energy of 13eV for hexagonal phase. The results, in comparison with the published data, are in good agreement with the experimental and previous theoretical results.
文摘The optical properties of CdBr2 were studied by first principle using the density functional theory. The dielectric functions and optical constants are calculated using the full potential-linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA). The theoretical calculated optical properties and energy Loss (EEL) spectrum yield a static refractive index of 2.1 and a plasmon energy of 13eV for hexagonal phase. The results, in comparison with the published data, are in good agreement with the experimental and previous theoretical results.
文摘The equilibrium crystal structure parameter and bulk modulus of the SrMoO3 perovskite has been calculated with ab-initio method based on density functional theory (DFT) using both local density approximation (LDA) and generalized gradient approximation (GGA). The corresponding total free energy along with its various components for SrMoO3 was obtained. The lattice parameter and bulk modulus calculated for SrMoO3 within LDA are 3.99 A and 143.025 GPa respectively whereas within GGA are 4.04 A and 146.14 GPa respectively, both agree well with the available experimental data. The total energy calculated within LDA and GGA is almost the same however lower results are obtained for GGA. All calculations have been carried out using ABINIT computer code.
基金Supported by the National Natural Science Foundation of China (Grants Nos. 20273034 & 20673063)
文摘First principles density functional theory calculations have been performed for the chemisorption of formate adsorption on some metal surfaces. For the most stable adsorption site of short-bridge, the calculated formate adsorption energy follows the order of Au(110) < Ag(110) < Cu(110) < Pd(110) < Pt(110) < Ni(110) < Rh(110) < Fe(100) < Mo(100), and a clear linear correlation exists between the adsorption energy and the corresponding heat of formation of metal oxides. Moreover, it has been found that the formate adsorption energy for the transition metals can be correlated well with its d-band center (εd), and the IB Group metals can be described by the coupling matrix element square (Vad2).
基金Supported by Islamic Azad University,Kermanshah branch,Kermanshah,Iran
文摘The electronic and optical properties of 2D Cu_2Si and Cu_2Si:Ti are investigated based on the density functional theory(DFT) using the FP-LAPW method and GGA approximation. The 2D Cu_2Si has metallic and non magnetic properties, whereas adding Ti impurity to its structure changes the electronic behavior to the half-metallic with 3.256μB magnetic moment. The optical transition is not occurred in the infrared and visible area for the 2D Cu_2Si in x-direction and by adding Ti atom, the real part of dielectric function in the x-direction, Re(ε(ω))_x is reached to a Dirac peak at this energy range. Moreover, the absorption gap tends to zero in x-direction of the 2D Cu_2Si:Ti.
