The structural, electronic, optical, and elastic properties of Cu_2MgSnS_4 in four crystalline phases（wurtzite-stannite（WS）, stannite（ST）, kesterite（KS）, and primitive-mixed Cu Au（PMCA）） are investigated usi...The structural, electronic, optical, and elastic properties of Cu_2MgSnS_4 in four crystalline phases（wurtzite-stannite（WS）, stannite（ST）, kesterite（KS）, and primitive-mixed Cu Au（PMCA）） are investigated using density functional theory（DFT） in the framework of the full potential linearized augmented plane wave plus local-orbitals（FP-LAPW＋lo） method within the generalized gradient approximation based on the Perdew 2008 functional（GGA-PBEsol）. For each phase, the structural parameters, bulk modulus, and its pressure derivative are calculated. The relative stability of these phases is also discussed. In addition, the elastic constants have been calculated in order to investigate the mechanical stability of all phases. Moreover, the anisotropy factor, shear modulus, Young＇s modulus, Lame＇s coefficient, and Poisson＇s ratio have been estimated from the calculated single crystalline elastic constants. For the band structure, the density of states and optical properties of the exchange and correlation effects are treated by the Tran-Blaha modified Becke-Johnson potential to give a better description of the band-gap energies and optical spectra. The obtained results are compared with available experimental data and to other theoretical calculations.展开更多
The refractive index ofas-evaporatedamorphous semiconductor As2S8 film upon an annealing and saturation irradiation and annealing cycle is reversible. Upon successive treatment with annealing and non-saturation irradi...The refractive index ofas-evaporatedamorphous semiconductor As2S8 film upon an annealing and saturation irradiation and annealing cycle is reversible. Upon successive treatment with annealing and non-saturation irradiation and further annealing, the refractive index of the as-evaporated amorphous semiconductor As2S8 film reaches a maximum value and then its reversibility occurs upon annealing. The annealing of the amorphous semiconductor AS2S8 films results in the stabilization of the structure through changes of the S-S bonds in the nearest environment, accompanied by a decrease of film thickness. The As2S8 planar waveguide after annealing （130 ℃） and saturation irradiation and annealing （130 ℃） shows a good propagation characteristic with ca, 0.27 dB/cm low propagation loss of the 632.8 nm guided mode.展开更多
文摘The structural, electronic, optical, and elastic properties of Cu_2MgSnS_4 in four crystalline phases（wurtzite-stannite（WS）, stannite（ST）, kesterite（KS）, and primitive-mixed Cu Au（PMCA）） are investigated using density functional theory（DFT） in the framework of the full potential linearized augmented plane wave plus local-orbitals（FP-LAPW＋lo） method within the generalized gradient approximation based on the Perdew 2008 functional（GGA-PBEsol）. For each phase, the structural parameters, bulk modulus, and its pressure derivative are calculated. The relative stability of these phases is also discussed. In addition, the elastic constants have been calculated in order to investigate the mechanical stability of all phases. Moreover, the anisotropy factor, shear modulus, Young＇s modulus, Lame＇s coefficient, and Poisson＇s ratio have been estimated from the calculated single crystalline elastic constants. For the band structure, the density of states and optical properties of the exchange and correlation effects are treated by the Tran-Blaha modified Becke-Johnson potential to give a better description of the band-gap energies and optical spectra. The obtained results are compared with available experimental data and to other theoretical calculations.
基金supported by the National Natural Science Foundation of China(Nos.60967003,61077042)the Scientific Research Program Foundation of Jiangxi Provincial Education Department,China(No.GJJ11303)
文摘The refractive index ofas-evaporatedamorphous semiconductor As2S8 film upon an annealing and saturation irradiation and annealing cycle is reversible. Upon successive treatment with annealing and non-saturation irradiation and further annealing, the refractive index of the as-evaporated amorphous semiconductor As2S8 film reaches a maximum value and then its reversibility occurs upon annealing. The annealing of the amorphous semiconductor AS2S8 films results in the stabilization of the structure through changes of the S-S bonds in the nearest environment, accompanied by a decrease of film thickness. The As2S8 planar waveguide after annealing （130 ℃） and saturation irradiation and annealing （130 ℃） shows a good propagation characteristic with ca, 0.27 dB/cm low propagation loss of the 632.8 nm guided mode.
