Band structure calculations on the monoclinic bulk and nano-SrAl2O4 crystals

The electronic structure of SrAl2O4 is calculated by density functional method and exchange and correlation have been treated by the generalized gradient approximation within the scheme due to Perdew-Burke-Ernzerhof. The bond length and bond covalency are also calculated by chemical bond method. Compared with the SrAl2O4 bulk crystal, the bond covalency of nanocrystal has an increasing trend; its band gap also is wider; the bond lengths of SrAl2O4 nanocrystal become shorter, which is responsible for the change of the covalency and band gap.