Chemical bonding as well as structural,electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functio...Chemical bonding as well as structural,electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functional theory(DFT).The calculated lattice constant is found to be in good agreement with the experimental results.The electron density plots reveal strong ionic bonding in Cs-F and strong covalent bonding in Pb-F.The calculations show that the material is a direct and wide bandgap semiconductor with a fundamental gap at the R-symmetry point.Optical properties such as the real and imaginary parts of the dielectric function,refractive index,extinction coefficient,reflectivity,optical conductivity and absorption coefficient are also calculated.Based on the calculated wide and direct bandgap,as well as other optical properties of the compound,it is predicted that CsPbF_(3) is suitable for optoelectronic devices and anti-reflecting coatings.展开更多
A first-principles technique capable of describing the nearly excited states of semiconductors and insulators,namely the modified Becke–Johnson(mBJ)potential approximation,is used to investigate the electronic band s...A first-principles technique capable of describing the nearly excited states of semiconductors and insulators,namely the modified Becke–Johnson(mBJ)potential approximation,is used to investigate the electronic band structure and optical properties of spinel oxides:GeZn_(2)O_(4).The predicted band gaps using the mBJ approximation are significantly more accurate than the proposed previous theoretical work using the common LDA and GGA.Band gap dependent optical parameters,like the dielectric constant,index of refraction,reflectivity and optical conductivity are calculated and analyzed.The results from the dielectric constant shows that the numerical value of the static dielectric,after dropping constantly,becomes less than zero and the material exhibits metallic behavior.The refractive index also drops below unity for photons higher than 18 eV,which indicates that the velocities of incident photons are greater than the velocity of light.However,these phenomena can be explained by the fact that a signal must be transmitted as a wave packet rather than a monochromatic wave.This comprehensive theoretical study of the optoelectronic properties predicts that these materials can effectively be used in optical devices.展开更多
文摘Chemical bonding as well as structural,electronic and optical properties of CsPbF3 are calculated using the highly accurate full potential linearized augmented plane-wave method within the framework of density functional theory(DFT).The calculated lattice constant is found to be in good agreement with the experimental results.The electron density plots reveal strong ionic bonding in Cs-F and strong covalent bonding in Pb-F.The calculations show that the material is a direct and wide bandgap semiconductor with a fundamental gap at the R-symmetry point.Optical properties such as the real and imaginary parts of the dielectric function,refractive index,extinction coefficient,reflectivity,optical conductivity and absorption coefficient are also calculated.Based on the calculated wide and direct bandgap,as well as other optical properties of the compound,it is predicted that CsPbF_(3) is suitable for optoelectronic devices and anti-reflecting coatings.
文摘A first-principles technique capable of describing the nearly excited states of semiconductors and insulators,namely the modified Becke–Johnson(mBJ)potential approximation,is used to investigate the electronic band structure and optical properties of spinel oxides:GeZn_(2)O_(4).The predicted band gaps using the mBJ approximation are significantly more accurate than the proposed previous theoretical work using the common LDA and GGA.Band gap dependent optical parameters,like the dielectric constant,index of refraction,reflectivity and optical conductivity are calculated and analyzed.The results from the dielectric constant shows that the numerical value of the static dielectric,after dropping constantly,becomes less than zero and the material exhibits metallic behavior.The refractive index also drops below unity for photons higher than 18 eV,which indicates that the velocities of incident photons are greater than the velocity of light.However,these phenomena can be explained by the fact that a signal must be transmitted as a wave packet rather than a monochromatic wave.This comprehensive theoretical study of the optoelectronic properties predicts that these materials can effectively be used in optical devices.
