Two-channel Kondo tunneling in triple quantum dot

Kuzmenko, T.; Kikoin, K.; Avishai, Y.

Two-channel Kondo tunneling in triple quantum dot

Authors

Kuzmenko, T.

Kikoin, K.

Avishai, Y.

Description

The effective spin Hamiltonian of a triple quantum dot with odd electron occupation weakly connected in series with left ($l$) and right ($r$) metal leads is composed of two-channel exchange and co-tunneling terms. Renormalization group equations for the corresponding three exchange constants $J_{l}$, $J_{r}$ and $J_{lr}$ are solved (to third order). Since $J_{lr}$ is relevant, the system is mapped on an anisotropic two-channel Kondo problem. The structure of the conductance as function of temperature and gate voltage implies that in the weak and intermediate coupling regimes, two-channel Kondo physics persists at temperatures as low as several $T_{K}$. At even electron occupation, the number of channels equals twice the spin of the triple dot (hence it is a fully screened impurity).
4 revtex pages with 4 .eps figures