Shot noise and tunnel magnetoresistance in multilevel quantum dots: Effects of cotunneling

Abstract

Spin-dependent transport through a multilevel quantum dot weakly coupled to ferromagnetic leads is analyzed theoretically by means of the real-time diagrammatic technique. Both the sequential and cotunneling processes are taken into account, which makes the results on tunnel magnetoresistance (TMR) and shot noise applicable in the whole range of relevant bias and gate voltages. Suppression of the TMR due to inelastic cotunneling and super-Poissonian shot noise have been found in some of the Coulomb blockade regions. Furthermore, in the Coulomb blockade regime there is an additional contribution to the noise due to bunching of cotunneling processes involving the spin-majority electrons. On the other hand, in the sequential tunneling regime TMR oscillates with the bias voltage, while the current noise is generally sub-Poissonian.

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Cited by in corpus (7)

• Spin effects in single electron tunneling
• Effects of different geometries on the conductance, shot noise and tunnel magnetoresistance of double quantum dots
• Probing the exchange field of a quantum-dot spin valve by a superconducting lead
• Transport through single-wall metallic carbon nanotubes in the cotunneling regime
• Influence of spin waves on transport through a quantum-dot spin valve
• Iterative path-integral summations for the tunneling magnetoresistance in interacting quantum-dot spin valves
• Shot noise in a quantum dot coupled to non-magnetic leads: Effects of Coulomb interaction