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Climbing the Entropy Barrier: Driving the Single- towards the Multichannel Kondo Effect by a Weak Coulomb Blockade of the Leads

S. Florens·A. Rosch
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Abstract

We study a model proposed recently in which a small quantum dot is coupled symmetrically to several large quantum dots characterized by a charging energy E_c. Even if E_c is much smaller than the Kondo temperature T_K, the long-ranged interactions destabilize the single-channel Kondo effect and induce a flow towards a multi-channel Kondo fixed point associated with a rise of the impurity entropy with decreasing temperature. Such an ``uphill flow'' implies a negative impurity specific heat, in contrast to all systems with local interactions. An exact solution found for a large number of channels allows us to capture this physics and to predict transport properties.

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S. Florens, A. Rosch. 2004-05-26. Climbing the Entropy Barrier: Driving the Single- towards the Multichannel Kondo Effect by a Weak Coulomb Blockade of the Leads. https://doi.org/10.1103/physrevlett.92.216601

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