Taking advantage of light- and heavy-hole trions for optical spin initialization, control and readout

Optical control strategies in semiconductor nanostructures have almost exclusively relied on heavy-hole exciton and trion states. In the first part of this letter, we show that light-hole trions provide the missing ressource for consolidating all single qubit operations in a mutually compatible magnetic field configuration: electron spin initialization and control can be achieved through light-hole trion states and cycling transition is provided by heavy-hole trion states. In the second part, we experimentally demonstrate that pairs of nitrogen atoms in GaAs exhibiting a Cs symmetry bind both light- and heavy-hole excitons and negative trions. A detailed analysis of the fine structure reveals that that trion states provide the lambda level structure necessary for fast initialization and control along with energetically-protected cycling transition compatible with single-shot readout.