Accurate calculation of polarization-related quantities in   semiconductors
  We demonstrate that polarization-related quantities in semiconductors can be predicted accurately from first-principles calculations using the appropriate approach to the problem, the Berry-phase polarization theory. For III-V nitrides, our test case, we find polarizations, polarization differences between nitride pairs, and piezoelectric constants quite close to their previously established values. Refined data are nevertheless provided for all the relevant quantities. 
F. Bernardini, V. Fiorentini (Cagliari), D. Vanderbilt (Rutgers)