  Electron spin qubit coherence in quantum dots is ultimately limited by random
nuclear spin bath fluctuations. Here we aim to eliminate this randomness by
making spin bath evolution deterministic. We introduce spin bath control
sequences, which systematically combine Hahn and solid echoes to suppress
inhomogeneous broadening and nuclear-nuclear interactions. Experiments on
self-assembled quantum dots show a five-fold increase in nuclear spin
coherence. Numerical simulations show that these sequences can be used to
suppress decoherence via qubit-qubit interaction in point defect and dopant
spin systems.
