Potentiometric measurements of the spin-split subbands in a two-dimensional electron gas

The density of states of carriers in a high-mobility InAs single quantum well is spin split by the Rashba effect. The asymmetry favors down-spin states for carriers with positive momentum and up-spin states for carriers with negative momentum. Imposing a bias current causes inequivalent shifts of the spin subband chemical potential, which are detected using a ferromagnetic film electrode and an open circuit voltage measurement. Measurements made on three samples over a range $77<T<\mathrm{}296\mathrm{}\mathrm{K}$ demonstrate spin detection at a ferromagnet-semiconductor interface and corroborate earlier experimental results of spin-dependent interfacial resistance.