First-principles study on piezoelectric and electro-optical properties of ZnX (X = O, S, Se, Te)

First-principles calculations are performed to investigate linear electro-optical tensors and piezoelectric constants for zinc-blende compounds ZnX (X = O, S, Se, Te). The obtained results are compared with experimental and other theoretical results available. The findings are the followings: (1) there is no soft mode in these compounds because the electronic contributions and ionic contributions to the dielectric constants are of the same order of magnitude; (2) ZnO is the best candidate as an electro-optical material because of its largest electronic contribution to electro-optical effect among zinc-blende ZnX (X = O, S, Se, Te) compounds; (3) the abilities to resist volume compression, elastic deformation and linear compression reduce, and the second-order piezoelectric coefficients B 114 p become small from X = O to X = Te for ZnX (X = O, S, Se, Te) in turn.