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

TL;DR

This paper demonstrates that nuclear quadrupole interaction enhances electron-nuclear spin coherence in quantum dots by suppressing nuclear spin flips and electron spin decoherence, enabling improved spin memory and zero-field polarization.

Contribution

It reveals the stabilizing role of nuclear quadrupole interaction in extending spin coherence and enabling zero-field nuclear polarization in quantum dots.

Findings

Nuclear quadrupole interaction suppresses nuclear spin flips.

It enables zero-field dynamic nuclear polarization.

The interaction elongates electron-nuclear spin memory.

Abstract

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