Abstract:
Based on the modern polarization theory and first-principles calculation, the spontaneous polarization and piezoelectric constants of wurtzite ZnO, AlN and GaN are calculated by using the Berry phase method and maximally localized Wannier functions, respectively. The relations between spontaneous polarization and crystal structures are also investigated. The numerical results coincide with the previous reports, indicate that the spontaneous polarization and piezoelectric constants of AlN are the largest one among the three semiconductors. The spontaneous polarization of AlN is two times more than the other two. Comparing with the Berry phase method, due to the production of Wannier centers maximally localized Wannier functions has a unique advantage in analysing spontaneous polarization, electric structures and atomic bonding, which will give a more clear physical picture.
