Regensburg 2007 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 52: Transport properties

HL 52.6: Talk

Friday, March 30, 2007, 12:15–12:30, H14

Quality improvement of MBE grown 2D hole systems in GaAs/AlGaAs — •Christian Gerl, Johannes Bauer, Dieter Schuh, and Werner Wegscheider — Institut für Experimentelle & Angewandte Physik, Universität Regensburg

By introducing carbon as p-dopant for GaAs/AlGaAs heterosystems, restrictions from formerly used acceptor materials like beryllium and silicon have been overcome [1]. The carrier mobility in 2 dimensional hole systems (2DHS) reached values of 1.2x10^6 cm^2/Vs and 1.1x10^6 cm^2/Vs in the (001) and (110) growth directions, respectively [2]. This enhancement in sample quality is essential for detailed investigations on the non parabolic dispersion relation of 2DHSs.

We present magnetotransport measurements of ultra high mobility quantum well and modulation doped single interface structures directly revealing the effect of the structure inversion asymmetry on the Rashba spin-splitting. In addition promising ways to increase the sample quality even further and to prevent a hysteretic dependence of the hole density when an external electric field is applied are suggested.

[1] C. Gerl et al., Appl. Phys. Lett 86, 252105 (2005)

[2] S. Schmult et al. Appl. Phys. Lett 86, 202105 (2005)