Kondo Resonance versus Fano Interference in Double Quantum Dots Coupled to a Two-Lead One-Ring System
CHEN Xiong-Wen, SHI Zhen-Gang, CHEN Bao-Ju, SONG Ke-Hui
1Department of Physics and Electronic Information Science, Huaihua University, Huaihua 4180082Research Institute of Information Science, Huaihua University, Huaihua418008
Kondo Resonance versus Fano Interference in Double Quantum Dots Coupled to a Two-Lead One-Ring System
1Department of Physics and Electronic Information Science, Huaihua University, Huaihua 4180082Research Institute of Information Science, Huaihua University, Huaihua418008
摘要We analyse the transport properties of a coupled double quantum dot (DQD) device with one of the dots (QD1) coupled to metallic leads and the other (QD2) embedded in an Aharonov--Bhom (A-B) ring by means of the slave-boson mean-field theory. It is found that in this system, the Kondo resonance and the Fano interference exist simultaneously, the enhancing Kondo effect and the increasing hopping of the QD2-Ring destroy the localized electron state in the QD2 for the QD1-leads, and accordingly, the Fano interference between the DQD-leads and the QD1-leads are suppressed. Under some conditions, the Fano interference can be quenched fully and the single Kondo resonance of the QD1-leads comes into being. Moreover, when the magnetic flux of the A-B ring is zero, the influence of the parity of the A-B ring on the transport properties is very weak, but this influence becomes more obvious with non-zero magnetic flux. Thus this model may be a candidate for future device applications.
Abstract：We analyse the transport properties of a coupled double quantum dot (DQD) device with one of the dots (QD1) coupled to metallic leads and the other (QD2) embedded in an Aharonov--Bhom (A-B) ring by means of the slave-boson mean-field theory. It is found that in this system, the Kondo resonance and the Fano interference exist simultaneously, the enhancing Kondo effect and the increasing hopping of the QD2-Ring destroy the localized electron state in the QD2 for the QD1-leads, and accordingly, the Fano interference between the DQD-leads and the QD1-leads are suppressed. Under some conditions, the Fano interference can be quenched fully and the single Kondo resonance of the QD1-leads comes into being. Moreover, when the magnetic flux of the A-B ring is zero, the influence of the parity of the A-B ring on the transport properties is very weak, but this influence becomes more obvious with non-zero magnetic flux. Thus this model may be a candidate for future device applications.
[1] Hewson A C 1993 The Kondo Problem to Heavy Fermions(Cambridge: Cambridge University Press) [2] Gordon D G, Shtrikman H, Magder D A et al 1998 Nature 391 156 [3] Kang K and Shin S C 2000 Phys. Rev. Lett. 85 5619 [4] Affleck and Simon P 2001 Phys. Rev. Lett. 86 2854 [5] Bing D et al 2004 con-mat/0405538 [6] Martinek J, Utsumi Y and Imamura H te al 2003 Phys. Rev.Lett. 91 127203 [7] Cronenwett S, Oosterkamp T H and Kouwenhoven L P 1998 Science 281 540 [8] Zhou G H and Li Y 2005 J. Phys: Condens. Matter 17 6663 de Guevara M L L, Claro F and Orellana P A 2003 Phys. Rev. B 67 195335 [9] Johnson A C, Marcus C M and Hanson M P et al 2004 Phy. Rev.Lett. 93 106803 [10] Golub A and Avishai Y 2004 Phys. Rev. B 69 165325 [11] Tae-Suk K and Hershfield S 2001 Phys. Rev. B 63 245326 [12] Wu B H, Cao J C and Kang-Hun Ahn 2005 Phys. Rev. B 72 165313 [13] Zhou B, Wu S Q and Sun W L et al 2004 Chin. Phys. 13225 Wu S Q, Wang S J and Sun W L et al 2004 Chin. Phys. 13 510 [14] Chen X W, Wu S Q and Wang P et al 2004 Chin. Phys. Lett. 21 911
2007, Vol. 24 
