  Two closely spaced dangling bonds positioned on a silicon surface and sharing
an excess electron are revealed to be a strong candidate for a charge qubit.
Based on our study of the coherent dynamics of this qubit, its extremely high
tunneling rate ~ 10^14 1/s greatly exceeds the expected decoherence rates for a
silicon-based system, thereby overcoming a critical obstacle of charge qubit
quantum computing. We investigate possible configurations of dangling bond
qubits for quantum computing devices. A first-order analysis of coherent
dynamics of dangling bonds shows promise in this respect.
