Abstract
We measure the donor-bound electron longitudinal spin-relaxation time as a function of magnetic field in three high-purity direct band-gap semiconductors: GaAs, InP, and CdTe, observing a maximum of 1.4, 0.4, and 1.2 ms, respectively. In GaAs and InP at low magnetic field, up to T, the spin-relaxation mechanism is strongly density and temperature dependent and is attributed to the random precession of the electron spin in hyperfine fields caused by the lattice nuclear spins. In all three semiconductors at high magnetic field, we observe a power-law dependence with . Our theory predicts that the direct spin-phonon interaction is important in all three materials in this regime in contrast to quantum dot structures. In addition, the “admixture” mechanism caused by Dresselhaus spin-orbit coupling combined with single-phonon processes has a comparable contribution in GaAs. We find excellent agreement between high-field theory and experiment for GaAs and CdTe with no free parameters, however a significant discrepancy exists for InP.
5 More- Received 18 May 2016
DOI:https://doi.org/10.1103/PhysRevB.94.125401
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