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We theoretically investigate the effects of electronic correlations (including spin and Coulomb correlations) on the magnetotransport through a parallel double quantum dot (DQD) coupled to ferromagnetic leads. Two dots couple coherently through electron correlations, rather than tunneling directly between two dots, and each dot is coupled to two semi-infinite ferromagnetic leads. We assume that the intradot Coulomb repulsion is much larger than the interdot Coulomb repulsion U. Thus, only the zero, one and two-particle DQD states are relevant to transport. Because of interdot electron correlation, the I-V characteristics of each dot is sensitive to the change in the state of the other dot. This work focuses on the effects of electron spin correlation and electron Coulomb correlation on magnetotransport through this system. In order to determine the transport properties of the system, we use the generalized master equation method. This method is based on the reduced density operator defined by averaging the statistical operator of the total system over the states of all leads. With the framework of the generalized master equation and the sequential tunneling approximation, we calculate the current, differential conductance and tunnel magnetoresistance (TMR) in the dot 1 as a function of bias for different spin correlations and Coulomb correlations. Our results reveal that the magnetotransport through this system is more sensitive to Coulomb correlation than to spin correlation; when Coulomb correlation equals zero, the spin correlation can induce a giant tunnel magnetoresistance, which is further larger than the Jullieres value of TMR; when Coulomb correlation occurs, the giant tunnel magnetoresistance disappears; when Coulomb correlation is equal to or larger than spin correlation, Coulomb correlation can suppress spin correlation; while the coexistence of Coulomb correlation and asymmetry of the DQD system can result in dynamical channel blockade, which can lead to the occurrence of negative tunnel magetoresistance and negative differential conductance. These novel properties lead to the potential applications in nanoelectronics, and relevant underlying physics of this problem is discussed.
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Keywords:
- parallel double quantum dot /
- electronic correlations /
- master equation method /
- negative differential conductance and negative tunnel magetoresistance
[1] Zutic I, J Fabian J, Das Sarma S 2004 Rev. Mod. Phys. 76 323
[2] Loss D, DiVincenzo D P 1998 Phys. Rev. A 57 120
[3] Hanson R, Burkard G 2007 Phys. Rev. Lett. 98 050502
[4] Cottet A, Belzig W, Bruder C 2004 Phys. Rev. Lett. 92 206801
[5] Weymann I, König J, Martinek J, Barnaò J, Schön G 2005 Phys. Rev. B 72 115334
[6] Goldhaber-Gordon D, Shtrikman H, Mahalu D, Abusch D, Meirav U, Kastner M A 1998 Nature 391 156
[7] Cronenwett S M, Oosterkamp T H, Kouwenhoven L P 1998 Science 281 540
[8] Sun Q F, H Guo H, Lin T H 2001 Phys. Rev. Lett. 87 176601
[9] Hamaya K, Kitabatake M, Shibata K, Jung M, Ishida S, Taniyama T, Hirakawa K, Arakawa Y, Machida T 2009 Phys. Rev. Lett. 102 236806
[10] Buttiker M 1990 Phys. Rev. Lett. 65 2901
[11] Trocha P, Barnaò J 2007 Phys. Rev. B 76 165432
[12] Hornberger R, Koller S, Begemann G, Donarini A, Grifoni M 2008 Phys. Rev. B 77 245313
[13] Weymann I 2007 Phys. Rev. B 75 195339
[14] Wu S Q, He Z, Yan C H, Sun W L, Wang S J 2006 Acta Phys. Sin. 55 1413 (in Chinese) [吴绍全, 何忠, 阎从华, 孙威立, 王顺金 2006 物理学报 55 1413]
[15] Wu S Q 2009 Acta Phys. Sin. 58 4175 (in Chinese) [吴绍全 2009 物理学报 58 4175]
[16] McClure D T, DiCarlo L, Zhang Y, Engel H A, Marcus C M, Hanson M P, Gossard A C 2007 Phys. Rev. Lett. 98 056801
[17] Golovach V N, Loss D 2004 Phys. Rev. B 69 245327
[18] Cota E, Aguado R, Platero G 2005 Phys. Rev. Lett. 94 107202
[19] Weymann I 2008 Phys. Rev. B 78 045310
[20] Izumida W, Sakai O 2000 Phys. Rev. B 62 10260
[21] Jones B A, Varma C M, Wilkins W J 1988 Phys. Rev. Lett. 61 125
[22] Buttiker M 1990 Phys. Rev. Lett. 65 2901
[23] Buttiker M 1992 Phys. Rev. B 46 12485
[24] Trocha P, Barna J 2007 Phys. Rev. B 76 165432
[25] Zou C Y, Wu S Q, Zhao G P 2013 Acta Phys. Sin. 62 017201 (in Chinese) [邹承役, 吴绍全, 赵国平 2013 物理学报 62 017201]
[26] Blum K 1996 Density Matrix Theory and Applications (New York: Taylor & Francis)
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[1] Zutic I, J Fabian J, Das Sarma S 2004 Rev. Mod. Phys. 76 323
[2] Loss D, DiVincenzo D P 1998 Phys. Rev. A 57 120
[3] Hanson R, Burkard G 2007 Phys. Rev. Lett. 98 050502
[4] Cottet A, Belzig W, Bruder C 2004 Phys. Rev. Lett. 92 206801
[5] Weymann I, König J, Martinek J, Barnaò J, Schön G 2005 Phys. Rev. B 72 115334
[6] Goldhaber-Gordon D, Shtrikman H, Mahalu D, Abusch D, Meirav U, Kastner M A 1998 Nature 391 156
[7] Cronenwett S M, Oosterkamp T H, Kouwenhoven L P 1998 Science 281 540
[8] Sun Q F, H Guo H, Lin T H 2001 Phys. Rev. Lett. 87 176601
[9] Hamaya K, Kitabatake M, Shibata K, Jung M, Ishida S, Taniyama T, Hirakawa K, Arakawa Y, Machida T 2009 Phys. Rev. Lett. 102 236806
[10] Buttiker M 1990 Phys. Rev. Lett. 65 2901
[11] Trocha P, Barnaò J 2007 Phys. Rev. B 76 165432
[12] Hornberger R, Koller S, Begemann G, Donarini A, Grifoni M 2008 Phys. Rev. B 77 245313
[13] Weymann I 2007 Phys. Rev. B 75 195339
[14] Wu S Q, He Z, Yan C H, Sun W L, Wang S J 2006 Acta Phys. Sin. 55 1413 (in Chinese) [吴绍全, 何忠, 阎从华, 孙威立, 王顺金 2006 物理学报 55 1413]
[15] Wu S Q 2009 Acta Phys. Sin. 58 4175 (in Chinese) [吴绍全 2009 物理学报 58 4175]
[16] McClure D T, DiCarlo L, Zhang Y, Engel H A, Marcus C M, Hanson M P, Gossard A C 2007 Phys. Rev. Lett. 98 056801
[17] Golovach V N, Loss D 2004 Phys. Rev. B 69 245327
[18] Cota E, Aguado R, Platero G 2005 Phys. Rev. Lett. 94 107202
[19] Weymann I 2008 Phys. Rev. B 78 045310
[20] Izumida W, Sakai O 2000 Phys. Rev. B 62 10260
[21] Jones B A, Varma C M, Wilkins W J 1988 Phys. Rev. Lett. 61 125
[22] Buttiker M 1990 Phys. Rev. Lett. 65 2901
[23] Buttiker M 1992 Phys. Rev. B 46 12485
[24] Trocha P, Barna J 2007 Phys. Rev. B 76 165432
[25] Zou C Y, Wu S Q, Zhao G P 2013 Acta Phys. Sin. 62 017201 (in Chinese) [邹承役, 吴绍全, 赵国平 2013 物理学报 62 017201]
[26] Blum K 1996 Density Matrix Theory and Applications (New York: Taylor & Francis)
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