Regensburg 2013 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

HL: Fachverband Halbleiterphysik

HL 5: Spintronics: mainly interfaces and heterostructures

HL 5.5: Vortrag

Montag, 11. März 2013, 10:30–10:45, H16

Hole spin coherence in coupled GaAs/AlAs quantum wells — •Christian Gradl, Michael Kugler, Dieter Schuh, Dominique Bougeard, Christian Schüller, and Tobias Korn — Universität Regensburg, D-93040 Regensburg, Germany

We perform time-resolved Kerr rotation, as well as resonant spin amplification measurements, on an undoped, [100]-grown GaAs/AlAs double quantum well (QW) structure to resolve the spin dynamics of hole ensembles at low temperatures. The gated system consists of two QWs with different well widths, which we use for the spatial separation of the optically excited electron-hole pairs.

Thus we are able to build up a hole spin polarization with a spin lifetime of several nanoseconds in the narrower QW. On the other hand, we observe a tunable behaviour in the broader QW, where the spin dynamics are dominated either by holes or by electrons, depending on the gate voltage.

A system like this might expand the recent, very successful investigations on hole spins in [100]-grown, p-doped GaAs/AlGaAs QWs to different growth directions or other materials like InGaAs, where the difficulty of proper p-type doping has limited detailed observations, so far.