Cottet, Audrey and Choi, Mahn-Soo (2006) Magnetoresistance of a quantum dot with spin-active interfaces. PHYSICAL REVIEW B, 74 (23).
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We study the zero-bias magnetoresistance (MR) of an interacting quantum dot connected to two ferromagnetic leads and capacitively coupled to a gate voltage source Vg. We investigate the effects of the spin-activity of the contacts between the dot and the leads by introducing an effective exchange field in an Anderson model. This spin-activity makes easier negative MR effects, and can even lead to a giant MR effect with a sign tunable with Vg. Assuming a twofold orbital degeneracy, our approach allows one to interpret in an interacting picture the MR(Vg) measured by S. Sahoo et al. [Nature Phys. 1, 99 (2005)] in single wall carbon nanotubes with ferromagnetic contacts. If this experiment is repeated on a larger Vg range, we expect that the MR(Vg) oscillations are not regular like in the presently available data, due to Coulomb interactions.
|Subjects:||Physical Science > Nano objects|
Physical Science > Quantum phenomena
Physical Science > Nanomagnetics
|Deposited By:||Anuj Seth|
|Deposited On:||26 May 2009 13:51|
|Last Modified:||26 May 2009 13:51|
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