A Double Quantum Dot Spin Valve

Abstract

A most fundamental and longstanding goal in spintronics is to electrically tune highly efficient spin injectors and detectors, preferably compatible with nanoscale electronics. Here, we demonstrate all these points using semiconductor quantum dots (QDs), individually spin-polarized by ferromagnetic split-gates (FSGs). As a proof of principle, we fabricated a double QD spin valve consisting of two weakly coupled semiconducting QDs in an InAs nanowire (NW), each with independent FSGs that can be magnetized in parallel or anti-parallel. In tunneling magnetoresistance (TMR) experiments at zero external magnetic field, we find a strongly reduced spin valve conductance for the two anti-parallel configurations, with a single QD polarization of $\sim 27\%$. The TMR can be significantly improved by a small external field and optimized gate voltages, which results in a continuously electrically tunable TMR between $+80\%$ and $-90\%$. A simple model quantitatively reproduces all our findings, suggesting a gate tunable QD polarization of $\pm 80\%$. Such versatile spin-polarized QDs are suitable for various applications, for example in spin projection and correlation experiments in a large variety of nanoelectronics experiments.

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Cited by in corpus (10)

• Spin Cross-Correlation Experiments in an Electron Entangler
• Anomalous Fano Resonance in Double Quantum Dot System Coupled to Superconductor
• Large voltage-tunable spin valve based on a double quantum dot
• Coupling in Quantum Dot Molecular Hetero-Assemblies
• Hysteretic magnetoresistance in nanowire devices due to stray fields induced by micromagnets
• Nonequilibrium spintronic transport through Kondo impurities
• Spin Seebeck effect of correlated magnetic molecules
• Spintronics with a Weyl point in superconducting nanostructures
• Precession of entangled spin and pseudospin in double quantum dots
• Using near-flat-band electrons for read-out of molecular spin qubit entangled states