Recombination kinetics of acceptor-bound holes in heterostructures: A probe of the local configuration of magnetically frozen electron insulators.

Abstract

We show that the kinetics of recombination of holes bound at acceptors from a \ensuremath{\delta}-doped monolayer in a heterostructure with magnetically frozen two-dimensional (2D) electrons evolves according to the power law I(t)\ensuremath{\propto}${\mathit{t}}^{\mathrm{\ensuremath{-}}1}$. This behavior is universal for any kind of 2D electron insulator (ordered or disordered) in the ultra-quantum-limit and follows over a wide time range after the photoexcitation pulse. The difference between ordered and random insulating phases shows up at the longest time delays: The ordering of electrons into a Wigner lattice yields an asymptotical single lifetime decay tail, with a recombination rate whose temperature dependence is described by the characteristic Debye-Waller-type factor.