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Scaling analysis of Kondo screening cloud in a mesoscopic ring with an embedded quantum dot

Mikio Eto, Keio University, Japan

21.11.2013 at 12:00 


The Kondo effect is theoretically studied in a quantum dot embedded in a mesoscopic ring. In this Kondo problem, there are two characteristiclengths, one is the screening length of the charge fluctuation (L_c) and the other is that of the spin fluctuation, or size of Kondo screeningcloud (L_K). Our scaling analysis yields analytical expressions for the Kondo temperature T_K and conductance in cases of (i) L_c << L_K << L,(ii) L_c << L << L_K, and (iii) L << L_c << L_K, where L is the ring size.T_K is markedly modulated by the magnetic flux \phi penetrating the ringin cases (ii) and (iii), whereas it hardly depends on \phi in case (i) [1]. This system should be also useful to examine the elastic and inelastic transport processes in the Kondo regime. We discuss the separation of the processes using the theory of ref.[2].

[1] R. Yoshii and M. Eto, Phys. Rev. B 83, 165310 (2011).

[2] G. Zarand et al., Phys. Rev. Lett. 93, 107204 (2004).

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