Studies of electronic structures and optical properties for rhombohedral CeAlO3 and PrAlO3 under pressure

The electronic structures of rhombohedral CeAlO3 and PrAlO3 are investigated under different pressures with the method of Heyd-Scuseria-Ernzerhof screened hybrid functional. The same downward trend is observed for the lattice constant and the band gap as the pressure increases. The results of optical properties show that epsilon(1) (0) increases continuously with the increasing pressure, and the same trend for main peak of epsilon(2)(omega) is obviously obtained. Prominent peaks of alpha(omega) , R(omega) and L(omega) have distinct blue-shift with the increase of the pressure. The peak of epsilon(2)(omega) for CeAlO3 is lower than that of PrAlO3. The peak intensity of L(omega) of CeAlO3 was higher than that of PrAlO3.