Fred H. Pollak

Valence band symmetry and deformation potentials of ZnO

Abstract The negative spin-orbit splitting of the valence band at k = 0 in ZnO, as proposed by Thomas and Hopfield, has been confirmed experimentally by measuring the effect of static uniaxial compression along the c-axis on the exciton spectrum of ZnO at 77°K. Four deformation potentials have been determined and are compared with the previously obtained values for CdS.

Energy band structure of germanium and gallium arsenide: The k.p method☆

Abstract The energy bands of germanium, valid throughout the entire Brillouin zone, have been obtained by diagonalizing a k . p Hamiltonian referred to 15 states at k = 0. The band structure of GaAs has been calculated by adding six independent matrix elements of an antisymmetric potential V − to the 15 × 15 k . p Hamiltonian of germanium.

Electroreflectance and band structure of gray tin

Abstract The electroreflectance spectrum of gray tin in the 1–5 eV region is reported. Nine peaks are observed and assigned to direct interband transitions at critical points. A semiempirical band structure, calculated with due regard of spin-orbit interaction by the k . p . method, incorporating the electroreflectance gaps and the Groves-Paul model is presented.

Optical constants of germanium and gray tin the k. p method

Abstract The imaginary parts of the dielectric constants of germanium and gray tin have been calculated from the previously obtained k . p band structures of these materials. Spin-orbit coupling effects have been included in the gray tin calculation. The results of these calculations are compared with experimental data.

Intrinsic piezobirefringence of AlSb

Abstract We have measured the intrinsic stress-induced birefringence of AlSb in the 0.4–1.7 eV range. The measurements were performed at room temperature for stresses along the [111] and the [100] directions up to 4 × 109 dyn/cm2. The results are compared with those obtained for Ge, Si, and GaAs. An attempt is made to fit the observed piezobirefringence with the sum of three dispersion processes: the energy gap at k = 0 (E0, E0 + Δ0), the E1, E1 + Δ1 gap, and a strong dispersion center at higher energies (either E01 or E2).

Magnetic field-modulated magnetoreflectance in germanium at 1.7°K

Abstract The effects of magnetic field modulation on the magnetoreflectance spectra of the direct edge (Γ 3 2 25′ → Γ 2′ ) in germanium at 1.7°K have been studied. The results of this experiment demonstrate that magnetic field modulation, which enhances high quantum number transitions, is a very useful technique for the study of interband magnetooptical properties of semiconductors.