Phase transition, spin-charge separation, and spin filtering in a quantum dot

Abstract

We consider low temperature transport through a lateral quantum dot asymmetrically coupled to two conducting leads, and tuned to the mixed-valence region separating two adjacent Coulomb blockade valleys with spin S=1/2 and S=1 on the dot. We demonstrate that this system exhibits a quantum phase transition driven by the gate voltage. In the vicinity of the transition the spin on the dot is quantized, even though the fluctuations of charge are strong. The spin-charge separation leads to an unusual Fano-like dependence of the conductance on the gate voltage and to an almost perfect spin polarization of the current through the dot in the presence of a magnetic field.

References in corpus (13)

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• Kondo effect in quantum dots
• Kondo effect in real quantum dots
• Two-stage Kondo effect in a quantum dot at high magnetic field
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• Cotunneling Spectroscopy in Few-Electron Quantum Dots
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• Mesoscopic fluctuations of the ground state spin of a small metal particle
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Cited by in corpus (12)

• Universal transport signatures in two-electron molecular quantum dots: gate-tunable Hund's rule, underscreened Kondo effect and quantum phase transitions
• Quantum phase transitions in the systems of parallel quantum dots
• Correlated electron physics in multilevel quantum dots: phase transitions, transport, and experiment
• Ground state of the parallel double quantum dot system
• Common non-Fermi liquid phases in quantum impurity physics
• Enhanced spin Hall effect by tuning antidot potential: Proposal for a spin filter
• Magnetic field effects in few-level quantum dots: theory, and application to experiment
• Underscreened Kondo effect in quantum dots coupled to ferromagnetic leads
• Spin current generation and detection by a double quantum dot structure
• Temperature dependence of electronic transport through molecular magnets in the Kondo regime
• Exchange interaction between two quantum dots coupled through a superconducting island
• Kondo temperature of a quantum dot