Sources of negative tunneling magnetoresistance in multilevel quantum dots with ferromagnetic contacts

TY - JOUR

T1 - Sources of negative tunneling magnetoresistance in multilevel quantum dots with ferromagnetic contacts

AU - Koller, Sonja

AU - Grifoni, Milena

AU - Paaske, Jens

PY - 2012/1/13

Y1 - 2012/1/13

N2 - 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, among them of excited states, can qualitatively influence the TMR effect.

AB - 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, among them of excited states, can qualitatively influence the TMR effect.

KW - Faculty of Science

KW - Condensed matter physics

KW - Nano electronics

U2 - 10.1103/PhysRevB.85.045313

DO - 10.1103/PhysRevB.85.045313

M3 - Journal article

SN - 0163-1829

VL - 85

SP - 045313

JO - Physical Review B Condensed Matter

JF - Physical Review B Condensed Matter

IS - 4

ER -