Spin‐Orbit Splitting of the Valence Band of Wurtzite Type Crystals

Abstract

A 12 x 12 representation is given of the valence band Hamiltonian a t k = 0 which includes the spin-orbit interaction. Expressions are derived for the energies and the linear combinations of the wave functions for the r,, r,, and re subbands. The whole valence band is completely determined by eight parameters: three energies, two parameters coupling states of equal spin, and three parameters coupling states of opposite spin. In principle, all parameters can be obtained experimentally from the energy separations and oscillator strengths for interband transitions for polarization 1 c and 11 c. Anisotropic spin-orbit interaction and mixing of states originating from the two anions per unit cell are discussed.

On correlation of CdS and CdSe valence band parameters

“…(3) coincides with the relation for effective mass of holes, given in Ref. [6], writing C 1 =q 2 / (1Àq 2 ) with empiric value q 2 depending on spin-orbital contribution to C 7 band [7]. The right-hand side of the formula (2) of Ref.…”

“…The most fundamental papers considering the definition of hole effective masses for CdS and CdSe are the papers of Cardona [3], Mahan and Hopfield [5], and Gutsche and Jahne [6][7][8]. The detailed analysis of their …”

“…The right-hand side of the formula (2) of Ref. [8] features the coefficient jT jÀjRj jQjÀjSj uC 0 in place of exact value 2; however, this coefficient could be estimated as 1.86 for CdS and 2.04 for CdSe, taking into account the values of matrix elements Q, R, S, and T [6][7][8]. To our opinion, such a discrepancy in values is caused by approximate graphical methods applied to determine parameters of band interaction necessary for analysis of dispersion curves E(k).…”

“…To obtain realistic calculation data, one needs to know the whole set of parameters describing materials used for each component of the device. Both CdS and CdSe have extensive experimental and theoretically predicted data published, including information on secondary energy gaps separating conduction band extremes in the center of Brillouin zone and the components of effective mass tensor (e.g., [3][4][5][6][7][8]). However, these effective mass data are in significant disagreement regarding the values published in different sources.…”

Mott Transition in CdS Revealed by Picosecond Nonlinear Absorption Measurements

“…The contributions depend on the polarization of light: the oscillator strengths are [9] 1, 0.61, 0.39 for polarization E I c and 0, 0.78, 1.22 for E I( c, relative to the A exciton with the value of 4nPA = 0.0125 [lo].…”