Electron Spin-Relaxation Times of Phosphorus Donors in Silicon

Electron paramagnetic resonance of ensembles of phosphorus donors in silicon has been detected electrically with externally applied magnetic fields lower than 200 G. Because the spin Hamiltonian was dominated by the contact hyperfine term rather than by the Zeeman terms at such low magnetic fields, superposition states $ \alpha{}| \uparrow \downarrow >+\beta{}| \downarrow \uparrow >$ and $-\beta{}| \uparrow \downarrow > + \alpha{}| \downarrow \uparrow >$ were formed between p...

We demonstrate a method which can hyperpolarize both the electron and nuclear spins of 31P donors in Si at low field, where both would be essentially unpolarized in equilibrium. It is based on the selective ionization of donors in a specific hyperfine state by optically pumping donor bound exciton hyperfine transitions, which can be spectrally resolved in 28Si. Electron and nuclear polarizations of 90% and 76%, respectively, are obtained in less than a second, providing an in...

We study two-electron singlet-triplet relaxation of donor-bound electrons in Silicon. Hyperfine interaction of the electrons with the phosphorus (P) nuclei, in combination with the electron-phonon interaction, lead to relaxation of the triplet states. Within the Heitler-London and effective mass approximations, we calculate the triplet relaxation rates in the presence of an applied magnetic field. This relaxation mechanism affects the resonance peaks in current Electron Spin ...

Electrical detection of spins is an essential tool in understanding the dynamics of spins in semiconductor devices, providing valuable insights for applications ranging from optoelectronics and spintronics to quantum information processing. For electron spins bound to shallow donors in silicon, bulk electrically-detected magnetic resonance has relied on coupling to spin readout partners such as paramagnetic defects or conduction electrons which fundamentally limits spin coher...

Decoherence of a shallow donor electron spin in silicon caused by electron-lattice interaction is studied. We find that there are two time scales associated with the evolution of the electron spin density matrix: the fast but incomplete decay due to the interaction with non-resonant phonons followed by slow relaxation resulting from spin flips accompanied by resonant phonon emission. We estimate both time scales as well as the magnitude of the initial drop of coherence for P ...

Erbium implanted silicon as a quantum technology platform has both telecommunications and integrated circuit processing compatibility. In Si implanted with Er to a concentration of 3x10^17 cm^3 and O to a concentration of 10^20 cm^3, the electron spin coherence time, T2, and the spin-lattice relaxation time, T1, were measured to be 7.5 ls and ~1 ms, respectively, at 5 K. The spin echo decay profile displayed strong modulation, which was consistent with the super-hyperfine int...

We investigate the spin species relevant for the spin-dependent recombination used for the electrical readout of coherent spin manipulation in phosphorus-doped silicon. Via a multi-frequency pump-probe experiment in pulsed electrically detected magnetic resonance, we demonstrate that the dominant spin-dependent recombination transition occurs between phosphorus donors and Si/SiO2 interface states. Combining pulses at different microwave frequencies allows us to selectively ad...

We study Si:P donor electron spin decoherence due to anisotropic hyperfine (AHF) interaction with the surrounding nuclear spin bath. In particular, we clarify the electron spin echo envelope modulation (ESEEM) in the Si:P system and the resonancelike contributions from nuclear spins in various shells away from the P atoms. We suggest an approach to minimize AHF-induced decoherence by avoiding the resonances and orienting an applied magnetic field along directions that can per...

When spin relaxation is governed by spontaneous emission of a photon into the resonator used for signal detection (the Purcell effect), the relaxation time $T_1$ depends on the spin-resonator frequency detuning $\delta$ and coupling constant $g$. We analyze the consequences of this unusual dependence for the amplitude and temporal shape of a spin-echo in a number of different experimental situations. When the coupling $g$ is distributed inhomogeneously, we find that the effec...

We demonstrate that the dynamic nuclear polarization (DNP) of phosphorus donors in silicon can be very effective in a magnetic field of 4.6 T and at temperatures below 1 K. The DNP occurs due to the Overhauser effect following a cross relaxation via the forbidden flip-flop or flip-flip transitions. Nuclear polarization values $P>0.98$ were reached after 20 min of pumping with 0.4 $\mu$W of microwave power. We evaluated that the ratio of hyperfine state populations increased b...