6→δ transition takes place at room temperature. The critical pressures of the β→P6 and P6→δ transformations are 42.9 and 47.7~GPa, respectively. The phase transition from P6→δ is accompanied by the volume shrinkage. The calculated results also show that the P6 and P6' phases belong to direct bandgap and indirect bandgap semiconductors, respectively. The calculated band gaps are 4.98 and 4.01 eV for the P6 and P6' phases, respectively. Besides, the static dielectric constants are also obtained. The reflectivity shows that the two phases can serve as the shielding and detecting devices for ultraviolet radiation and they have optical transparent behaviors in the visible light region.

"/>     Phase transition, electronic and optical properties of Si<sub>3</sub>N<sub>4</sub> new phases at high pressure with density functional theory
Acta Physica Sinica
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Acta Phys. Sin  2014, Vol. 63 Issue (4): 047101     doi:10.7498/aps.63.047101
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES Current Issue| Archive| Adv Search  |   
Phase transition, electronic and optical properties of Si3N4 new phases at high pressure with density functional theory
Yu Ben-Hai, Chen Dong
College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000, China
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