1.
Phys Rev Lett
; 109(10): 107401, 2012 Sep 07.
Article
in English
| MEDLINE
| ID: mdl-23005324
ABSTRACT
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 ns.