Spin-Singlet–Spin-Triplet Transitions in Quantum Dots
ABSTRACT We calculate the rate of the spin-singlet–spin-triplet (ST) relaxation in the two-electron droplet in a magnetic field. Far from the ST crossing point the rate turns out to be rather significant. In connection with the source-drain transport experiments, we consider this result is an explanation of the observed disappearance of the singlet (upper) level at magnetic fields, which are stronger than the ST crossing value.
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ABSTRACT: We describe time-dependent single-electron transport through quantum dots in the Coulomb blockade regime. Coherent dynamics of a single charge qubit in a double quantum dot is discussed with full one-qubit manipulation. Strength of decoherence is controlled with the applied voltage, but uncontrolled decoherence arises from electron–phonon coupling and background fluctuations. Then energy-relaxation dynamics is discussed for orbital and spin degree of freedom in a quantum dot. The electron–phonon interaction and spin–orbit coupling can be investigated as the dissipation problem. Finally, charge detection measurement is presented for statistical analysis of single-electron tunnelling transitions and for a sensitive qubit read-out device.Reports on Progress in Physics 02/2006; 69(3):759. · 14.72 Impact Factor