The electronic structures, optical dielectric functions, elastic properties, and lattice dynamics of Ba2ZnWO6 have been investigated by using the generalized gradient approximation. The density of states and distribut...The electronic structures, optical dielectric functions, elastic properties, and lattice dynamics of Ba2ZnWO6 have been investigated by using the generalized gradient approximation. The density of states and distributions of charge density show that O and Ba tend toward ionic bond, but O and W or Zn display the covalent bond character. The calculated energy band structure shows that Ba2ZnWO6 is a wide indirect band gap semiconductor. The static value 2.28 of the refractive index is attained. The analysis of the elastic properties of Ba2ZnWO6 indicates a rather weak elastic anisotropy. The phonon dispersion is calculated, suggesting no structural instability, which is agreement with the recent low temperature neutron diffraction experiments. The mensurability Cv （phonon heat capacity） as the function of the temperature is also calculated to judge our results for future experiment.展开更多
In this paper,we present calculations based on density functional theory using generalized gradient approximation(GGA)in double perovskite structure La_(2)BB'O_(6)(B,B'=3d transition metal)out of 45(C_(2)^(10)...In this paper,we present calculations based on density functional theory using generalized gradient approximation(GGA)in double perovskite structure La_(2)BB'O_(6)(B,B'=3d transition metal)out of 45(C_(2)^(10))combinational possibilities.Considering 4 types of magnetic states,namely,ferromagnetic(FM),ferrimagnetic(FiM),antiferromagnetics(AF),and nonmagnetic(NM)with full structure optimization,13 possible surviving,stable FM/FiM-HM materials containing 6 FM-HM materials(La_(2)ScNiO_(6),La_(2)CrCoO_(6),La_(2)CrNiO_(6),La_(2)VScO_(6),La_(2)VZnO_(6),and La_(2)VNiO_(6))and 7 FiM-HM materials(La_(2)VFeO_(6),La_(2)ZnCoO_(6),La_(2)TiCoO_(6),La_(2)CrZnO_(6),La_(2)CrMnO_(6),La_(2)ScFeO_(6),and La_(2)TiMnO_(6))are found.Considering the correlation effect(GGA+U),there are 6 possible half-metallic stable,surviving(HM)materials containing 3 FMHM materials(La_(2)ScNiO_(6),La_(2)CrCoO_(6),and La_(2)CrNiO_(6))and 3 FiM-HM materials(La_(2)VFeO_(6),La_(2)ZnCoO_(6),and La_(2)TiCoO_(6)).展开更多
基金supported by the Fundamental Research Funds for the Central Universities (Grant No. 2013QNA32)
文摘The electronic structures, optical dielectric functions, elastic properties, and lattice dynamics of Ba2ZnWO6 have been investigated by using the generalized gradient approximation. The density of states and distributions of charge density show that O and Ba tend toward ionic bond, but O and W or Zn display the covalent bond character. The calculated energy band structure shows that Ba2ZnWO6 is a wide indirect band gap semiconductor. The static value 2.28 of the refractive index is attained. The analysis of the elastic properties of Ba2ZnWO6 indicates a rather weak elastic anisotropy. The phonon dispersion is calculated, suggesting no structural instability, which is agreement with the recent low temperature neutron diffraction experiments. The mensurability Cv （phonon heat capacity） as the function of the temperature is also calculated to judge our results for future experiment.
基金the resource support from the Computational Materials Research Focus Group(CMRFG)the financial supports from the National Science Council(99B0320)+1 种基金the Center for General Education of National Normal Universitythe National Center for High-Performance Computing for computer time and facilities.
文摘In this paper,we present calculations based on density functional theory using generalized gradient approximation(GGA)in double perovskite structure La_(2)BB'O_(6)(B,B'=3d transition metal)out of 45(C_(2)^(10))combinational possibilities.Considering 4 types of magnetic states,namely,ferromagnetic(FM),ferrimagnetic(FiM),antiferromagnetics(AF),and nonmagnetic(NM)with full structure optimization,13 possible surviving,stable FM/FiM-HM materials containing 6 FM-HM materials(La_(2)ScNiO_(6),La_(2)CrCoO_(6),La_(2)CrNiO_(6),La_(2)VScO_(6),La_(2)VZnO_(6),and La_(2)VNiO_(6))and 7 FiM-HM materials(La_(2)VFeO_(6),La_(2)ZnCoO_(6),La_(2)TiCoO_(6),La_(2)CrZnO_(6),La_(2)CrMnO_(6),La_(2)ScFeO_(6),and La_(2)TiMnO_(6))are found.Considering the correlation effect(GGA+U),there are 6 possible half-metallic stable,surviving(HM)materials containing 3 FMHM materials(La_(2)ScNiO_(6),La_(2)CrCoO_(6),and La_(2)CrNiO_(6))and 3 FiM-HM materials(La_(2)VFeO_(6),La_(2)ZnCoO_(6),and La_(2)TiCoO_(6)).
