Electron spin relaxation as tracer of excitons in a two-dimensional electron-hole plasma inside a (110)-GaAs quantum well
Institute for Solid State Physics, University Hannover - 30167 Hannover, Germany, EU
2 Institute for Experimental and Applied Physics, University Regensburg - 93040 Regensburg, Germany, EU
3 Solid State Physics Laboratory, ETH Zürich - 8093 Zürich, Switzerland
Accepted: 4 November 2011
We show that a fast electron spin relaxation time in (110)-oriented GaAs/AlGaAs quantum wells is governed by the presence of excitons at low temperatures and intermediate excitation densities. The electron loses its spin orientation within an exciton due to the long-range part of the exciton anisotropic spin exchange interaction and unveils excitonic signatures within the many particle electron-hole system. The temperature-dependent time- and polarization-resolved photoluminescence measurements span five decades of carrier density, comprise the transition from localized excitons over quasi-free excitons to an electron-hole plasma, and reveal strong excitonic signatures even at relatively high densities and temperatures.
PACS: 71.35.-y – Excitons and related phenomena / 78.47.-p – Spectroscopy of solid state dynamics / 78.55.Cr – III-V semiconductors
© EPLA, 2011