THEORETICAL-STUDY OF MOMENTUM MATRIX-ELEMENTS OF GAN

The interaction between the conduction band and valence bands in wurtz ite GaN is theoretically investigated by means of the first-principles calculation and the k . p theory. The momentum matrix elements are de rived from the first-principles electronic band structure, calculated by a full-potential linearized augmented plane wave method. We also sh ow analytical expressions of the momentum matrix: elements, based on t he 8 x 8 k . p theory for the wurtzite structure. The values estimated from the analytical expressions are in good agreement with those obta ined from the first-principles calculation.