Stabilizing effect of nuclear quadrupole interaction on the polarization of electron-nuclear spin system in a quantum dot

摘要

Nuclear quadrupole interaction extends the limits imposed by hyperfineinteraction on the spin coherence of the electron and nuclei in a quantum dot.The strain-induced nuclear quadrupole interaction suppresses the nuclear spinflip and makes possible the zero-field dynamic nuclear polarization inself-organized InP/InGaP quantum dots. The direction of the effective nuclearmagnetic field is fixed in space, thus quenching the magnetic depolarization ofthe electron spin in the quantum dot. The quadrupole interaction suppresses thezero-field electron spin decoherence also for the case of non-polarized nuclei.These results provide a new vision of the role of the nuclear quadrupoleinteraction in nanostructures: it elongates the spin memory of theelectron-nuclear system.