Self-sustaining dynamical nuclear polarization oscillations in quantum dots

Abstract

Early experiments on spin-blockaded double quantum dots revealed surprising robust, large-amplitude current oscillations in the presence of a static (dc) source-drain bias [see e.g. K. Ono, S. Tarucha, Phys. Rev. Lett. 92, 256803 (2004)]. Experimental evidence strongly indicates that dynamical nuclear polarization plays a central role, but the mechanism has remained a mystery. Here we introduce a minimal albeit realistic model of coupled electron and nuclear spin dynamics which supports robust self-sustained oscillations. Our mechanism relies on a nuclear-spin analog of the tunneling magnetoresistance phenomenon (spin-dependent tunneling rates in the presence of an inhomogeneous Overhauser field) and nuclear spin diffusion, which governs dynamics of the spatial profile of nuclear polarization. The extremely long oscillation periods (up to hundreds of seconds) observed in experiments as well as the differences in phenomenology between vertical and lateral quantum dot structures are naturally explained in the proposed framework.

References in corpus (7)

• Singlet-triplet decoherence due to nuclear spins in a double quantum dot
• Measurement of Temporal Correlations of the Overhauser Field in a Double Quantum Dot
• Large nuclear Overhauser fields detected in vertically-coupled double quantum dots
• Stationary and transient leakage current in the Pauli spin blockade
• Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot
• Spin-dependent tunneling into an empty lateral quantum dot
• Magnetic field induced effects in the high source-drain bias current of weakly coupled vertical quantum dot molecules

Cited by in corpus (6)

• Nuclear Spin Dynamics in Double Quantum Dots: Multi-Stability, Dynamical Polarization, Criticality and Entanglement
• Preparation of Non-equilibrium Nuclear Spin States in Double Quantum Dots
• Interplay of spin-orbit and hyperfine interactions in dynamical nuclear polarization in semiconductor quantum dots
• Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime
• Role of dual nuclear baths on spin blockade leakage current bistabilities
• Entangling nuclear spins in distant quantum dots via an electron bus