Optical spin control and coherence properties of acceptor bound holes in strained GaAs

Hole spins in semiconductors are a potential qubit alternative to electron spins. In nuclear-spin-rich host crystals like GaAs, the hyperfine interaction of hole with nuclei is considerably weaker than that for electrons, leading potentially longer coherence times. Here we demonstrate optical pumping and coherent population trapping acceptor-bound holes strained GaAs epitaxial layer. We find $\mu$s-scale longitudinal spin relaxation time T$_1$ an inhomogeneous dephasing T$_2^*$ $\sim$7~ns. attribute mechanism combination effect hole-phonon through deformation potentials heavy-hole light-hole mixing in-plane magnetic field. short g-factor broadening due strain inhomogeneity. quantitatively calculated based on these mechanisms compared experimental results. While hyperfine-mediated decoherence mitigated, our results highlight important contribution