摘要
An investigation of structural stabilities, electronic and optical properties of SrF2 under high pressure is conducted using a first-principles calculation based on density functional theory （DFT） with the plane wave basis set as implemented in the CASTEP code. Our results predict that the second high-pressure phase of SrF2 is of a Ni2In- type structure, and demonstrate that the sequence of the pressure-induced phase transition of SrF2 is the fluorite structure （Fm3m） to the PbC12-type structure （Pnma）, and to the Ni2In-type phase （P63/mmc）. The first and second phase transition pressures are 5. 77 and 45.58 GPa, respectively. The energy gap increases initially with pressure in the Fm3m, and begins to decrease in the Pnma phases at 30 GPa. The band gap overlap metallization does not occur up to 210 GPa. The pressure effect on the optical properties is discussed.
An investigation of structural stabilities, electronic and optical properties of SrF2 under high pressure is conducted using a first-principles calculation based on density functional theory （DFT） with the plane wave basis set as implemented in the CASTEP code. Our results predict that the second high-pressure phase of SrF2 is of a Ni2In- type structure, and demonstrate that the sequence of the pressure-induced phase transition of SrF2 is the fluorite structure （Fm3m） to the PbC12-type structure （Pnma）, and to the Ni2In-type phase （P63/mmc）. The first and second phase transition pressures are 5. 77 and 45.58 GPa, respectively. The energy gap increases initially with pressure in the Fm3m, and begins to decrease in the Pnma phases at 30 GPa. The band gap overlap metallization does not occur up to 210 GPa. The pressure effect on the optical properties is discussed.
基金
Supported by the National Natural Science Foundation of China under Grant Nos 50771090 and 50821001, the National Basic Research Program of China under Grant No 2005CB724404, the Program for Changjiang Scholars and Innovative Team under Grant No IRT0650, and the Doctoral Foundation of Hebei Normal University of Science and Technology under Grant No 2008YB001.
