Spin Coherence of Holes in $\mathrm{GaAs}/(\mathrm{Al},\mathrm{Ga})\mathrm{As}$ Quantum Wells

Spin Coherence of Holes in $GaAs / (Al, Ga) As$ Quantum Wells

M. Syperek, D. R. Yakovlev, A. Greilich, J. Misiewicz, M. Bayer, D. Reuter, and A. D. Wieck

Phys. Rev. Lett. 99, 187401 – Published 29 October 2007

Abstract

Carrier spin coherence in a $p$ -doped $GaAs / (Al, Ga) As$ quantum well with a diluted hole gas is studied by picosecond pump-probe Kerr rotation. For resonant optical excitation of the positively charged exciton the spin precession shows two types of oscillations: Electron spin beats decaying with the charged exciton radiative lifetime of 50 ps, and long-lived hole spin beats with dephasing times up to 650 ps, which decrease with increasing temperature, underlining the importance of hole localization. The mechanism of hole spin coherence generation is discussed.