First-principles calculation of the piezoelectric tensor (d)over-left-right-arrow of III-V nitrides

We report direct first-principles density-functional calculations of the piezoelectric tensor ddown arrow relating polarization to applied stress for the binary compounds AlN, GaN, and InN. The values of ddown arrow are rather sensitive to the choice of the exchange-correlation functional, and results are presented for both the local-density and gradient approximations. A comparison with experiment and with values predicted indirectly from the elastic Cdown arrow and piezoconstant edown arrow tensors is also presented. (C) 2002 American Institute of Physics.