EXPERIMENTAL AND THEORETICAL APPROACH TO SPIN SPLITTING IN MODULATION-DOPED INXGA1-XAS INP QUANTUM-WELLS FOR B-]0/

Spin splitting of conduction-band energy levels in a modulation-doped InP/In0.77Ga0.23As/InP quantum well has been studied by Shubnikov-de H aas oscillations. By analyzing the characteristic beating pattern of t he oscillations the coupling constant alpha for spin-orbit interaction was determined. Biasing a gate on top of a Hall bat was used to modif y the strength of the spin-orbit coupling. The measured spin-orbit cou pling parameter alpha is quantitatively explained by utilizing a refin ed envelope-function-approximation theory for heterostructures.