Transport through two-level quantum dots weakly coupled to ferromagnetic leads

Abstract

Spin-dependent transport through a two-level quantum dot in the sequential tunneling regime is analyzed theoretically by means of a real-time diagrammatic technique. It is shown that the current, tunnel magnetoresistance, and shot noise (Fano factor) strongly depend on the transport regime, providing a detailed information on the electronic structure of quantum dots and their coupling to external leads. When the dot is asymmetrically coupled to the leads, a negative differential conductance may occur in certain bias regions, which is associated with a super-Poissonian shot noise. In the case of a quantum dot coupled to one half-metallic and one nonmagnetic lead, one finds characteristic Pauli spin blockade effects. Transport may be also suppressed when the dot levels are coupled to the leads with different coupling strengths. The influence of an external magnetic field on transport properties is also discussed.

12 pages, 8 figures

References in corpus (13)

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Cited by in corpus (11)

• Spin effects in single electron tunneling
• Effects of different geometries on the conductance, shot noise and tunnel magnetoresistance of double quantum dots
• Transport through quantum-dot spin valves containing magnetic impurities
• Cotunneling through quantum dots coupled to magnetic leads: zero-bias anomaly for non-collinear magnetic configurations
• Influence of spin waves on transport through a quantum-dot spin valve
• Shot noise and tunnel magnetoresistance in multilevel quantum dots: Effects of cotunneling
• Spin-polarized transport through weakly coupled double quantum dots in the Coulomb-blockade regime
• Thermal broadening of the Coulomb blockade peaks in quantum Hall interferometers
• Theory of transport through noncollinear single-electron spin-valve transistors
• Co-tunneling current through the two-level quantum dot coupled to magnetic leads: A role of exchange interaction
• Current fluctuations of noncollinear single-electron spin-valve transistors