Decoherence-avoiding spin qubits in optically active quantum dot   molecules
  In semiconductors, the T2* coherence time of a single confined spin is limited either by the fluctuating magnetic environment (via the hyperfine interaction), or by charge fluctuations (via the spin-orbit interaction). We demonstrate that both limitations can be overcome simultaneously by using two exchange-coupled electron spins that realize a single decoherence-avoiding qubit. Using coherent population trapping, we generate a coherent superposition of the singlet and triplet states of an optically active quantum-dot molecule, and show that the corresponding T2* may exceed 200 nanoseconds. 
K. M. Weiss, J. M. Elzerman, Y. L. Delley, J. Miguel-Sanchez and A.   Imamoglu
cond-mat.mes-hall