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We report theoretical and experimental studies of the longitudinal electron spin and orbital relaxation time of interstitial Li donors in $^{28}$Si. We predict that despite the near-degeneracy of the ground-state manifold the spin relaxation times are extremely long for the temperatures below 0.3 K. This prediction is based on a new finding of the chiral symmetry of the donor states, which presists in the presence of random strains and magnetic fields parallel to one of the cubic axes. Experimentally observed kinetics of magnetization reversal at 2.1 K and 4.5 K are in a very close agreement with the theory. To explain these kinetics we introduced a new mechanism of spin decoherence based on a combination of a small off-site displacement of the Li atom and an umklapp phonon process. Both these factors weakly break chiral symmetry and enable the long-term spin relaxation.
Substitutional donor atoms in silicon are promising qubits for quantum computation with extremely long relaxation and dephasing times demonstrated. One of the critical challenges of scaling these systems is determining inter-donor distances to achiev
We analyze the electron spin relaxation rate $1/T_1$ of individual ion-implanted $^{31}$P donors, in a large set of metal-oxide-semiconductor (MOS) silicon nanoscale devices, with the aim of identifying spin relaxation mechanisms peculiar to the envi
Modulation of donor electron wavefunction via electric fields is vital to quantum computing architectures based on donor spins in silicon. For practical and scalable applications, the donor-based qubits must retain sufficiently long coherence times i
We present easily reproducible experimental conditions giving long electron spin relaxation and dephasing times at low temperature in a quantum well. The proposed system consists in an electron localized by a donor potential, and immerged in a quantu
Compared with direct-gap semiconductors, the valley degeneracy of silicon and germanium opens up new channels for spin relaxation that counteract the spin degeneracy of the inversion-symmetric system. Here the symmetries of the electron-phonon intera