Sources of negative tunneling magneto-resistance in multilevel quantum dots with ferromagnetic contacts

Abstract

We analyze distinct sources of spin-dependent energy level shifts and their impact on the tunneling magnetoresistance (TMR) of interacting quantum dots coupled to collinearly polarized ferromagnetic leads. Level shifts due to virtual charge fluctuations can be quantitatively evaluated within a diagrammatic representation of our transport theory. The theory is valid for multilevel quantum dot systems and we exemplarily apply it to carbon nanotube quantum dots, where we show that the presence of many levels can qualitatively influence the TMR effect.

4 pages, 2 figures, supplemental material

References in corpus (9)

• Kondo effect in quantum dots coupled to ferromagnetic leads
• Electric-field controlled spin reversal in a quantum dot with ferromagnetic contacts
• Nanospintronics with carbon nanotubes
• Gate-controlled spin-splitting in quantum dots with ferromagnetic leads in the Kondo regime
• Magnetoresistance of a quantum dot with spin-active interfaces
• Transport through a double quantum dot system with non-collinearly polarized leads
• Linear and nonlinear transport across carbon nanotube quantum dots
• Spin transport across carbon nanotube quantum dots
• Non-Fermi liquid behavior in transport across carbon nanotube quantum dots

Cited by in corpus (10)

• Fabrication and characterisation of nanospintronic devices
• Spin resonance without spin splitting
• Transport across a carbon nanotube quantum dot contacted with ferromagnetic leads: experiment and non-perturbative modeling
• Transport across an Anderson quantum dot in the intermediate coupling regime
• Feynman-Vernon influence functional approach to quantum transport in interacting nanojunctions: An analytical hierarchical study
• Theory of spin pumping through an interacting quantum dot tunnel coupled to a ferromagnet with time-dependent magnetization
• Tunneling-induced renormalization in interacting quantum dots
• Transport in serial spinful multiple-dot systems: The role of electron-electron interactions and coherences
• Time-dependent quantum transport through an interacting quantum dot beyond sequential tunneling: second-order quantum rate equations
• Cotunneling renormalization in carbon nanotube quantum dots