Abstract
This work reports measurements of the diagonal thermopower in several heterojunctions based on Ga .47 In .53 As, in high magnetic fields and as a function of temperature. Structures have been studied in which only one or two electric subbands are populated, and in both cases the thermopower oscillations are in phase with the Shubnikov-de Haas oscillations in the resistivity, in accordance with theory. The absolute magnitude of the thermopower is found to be smaller than predicted by theory, and is also highly temperature dependent. © 1986.