Detection of anomalous Hall voltages in ultrahigh-mobility two-dimensional hole gases generated by optical spin orientation

By combining optical spin orientation and an externally applied longitudinal electric field, transverse charge accumulation has been detected in very high-mobility two-dimensional hole gases by measuring the transverse voltage drop across simple Hall devices. Our results indicate intrinsic band-structure (rather than extrinsic skew scattering) derived spin-orbit coupling as the underlying mechanism of this spin-polarized transport effect.

Figure 1

(a) The experimental arrangement. (b) Magnetic field dependence of $V_{\mathrm{TS}}$ at low magnetic field for the symmetric QW. (c) The dc current dependence of $V_{\mathrm{TS}}$ for the asymmetric QW. (d) $|V_{\mathrm{TS}}|$ vs laser helicity for the symmetric QW. The dashed line is a guide for the eye.

Figure 2

(a) Zero magnetic field right (${\sigma }^{+}$) and left (${\sigma }^{-}$) circularly polarized PLE spectra for the symmetric QW. Inset: circular polarization of that PLE. (b) Photon energy dependence of $V_{\mathrm{TS}}$ for the same symmetric QW. (c) Photon energy dependence of that $V_{\mathrm{TS}}$ at various magnetic fields. (d) Magnetic field dependence of those $V_{\mathrm{TS}}$ peak energies. (e) Magnetic field dependence of ${\sigma }^{+}$ (solid circles) and ${\sigma }^{-}$ (open circles) PLE peak energies for the same symmetric QW. The lines are guides for the eye and are explained in the text.

Figure 3

(a) $V_{\mathrm{TS}}$ (filled circles) and 2D hole gas mobility [16] (open circles) for the same symmetric QW as a function of temperature. (b) $V_{\mathrm{TS}}$ vs mobility. The line is a guide for the eye.