Electron spin relaxation times of phosphorus donors in silicon

Abstract

Pulsed electron paramagnetic resonance measurements of donor electron spins in natural phosphorus-doped silicon (Si:P) and isotopically-purified 28 Si:P show a strongly temperaturedependent longitudinal relaxation time, T 1 , due to an Orbach process with ∆E = 126 K. The 2-pulse echo decay is exponential in 28 Si:P, with the transverse relaxation (decoherence) time, T 2 , controlled by the Orbach process above ~12 K and by instantaneous diffusion at lower temperatures. Spin echo experiments with varying pulse turning angles show that the intrinsic T 2 of an isolated spin in 28 Si:P is ~60 ms at 7 K.

Electron Spin as a Spectrometer of Nuclear-Spin Noise and Other Fluctuations

“…Therefore this theory describes the irreversible decay of the effective hyperfine field produced by a pair of nuclear spins on the electron spin. Comparison with experiment [11,17,18,19,20] suggested reasonable order of magnitude agreement for the 1/e echo decay time (within a factor of 3) but poor qualitative agreement for the time dependence of the echo envelope. The next step was to develop a full quantum theory for the nuclear spin dynamics affecting the electron spin.…”

Suppression of spin-bath dynamics for improved coherence of multi-spin-qubit systems

“…Examples of such systems include nitrogen-vacancy (NV) colour centres in diamond 10 , phosphorous donors in silicon 11 and quantum dots 12 . In characterizing the potential usefulness of multi-qubit systems for quantum applications, the product of the qubit density (n qb ) and the qubit coherence lifetime (T 2 ) serves as a basic figure-of-merit (FOM), FOM = n qb T 2 .…”

Decoherence dynamics of a single spin versus spin ensemble

“…In standard NMR/ESR experiments, however, the observed signal comes from an ensemble with large number of spins, which are coupled to identical or structurally similar environments. [17][18][19][20] As an example, in this paper we consider a crystal containing paramagnetic impurity spins of one species, denoted below as species S, which are decohered by another dilute spin species I, with dipole-dipole coupling between S and I spins. One can think, for instance, of a frequently encountered situation 17,21 where S spins are paramagnetic centers in nonmagnetic crystal and I spins belong to another rare species: e.g., S could be the electron spin of a nitrogen-vacancy center in diamond, and I spins could be a bath of 13 C nuclear spins, 11,14 or the bath of the electron spins of nitrogen atoms ͑P1 centers͒.…”