Towards two-channel Kondo effect in triple quantum dot
Department of Physics, Ben-Gurion University - Beer-Sheva, Israel
2 Ilse Katz Center, Ben-Gurion University - Beer-Sheva, Israel
Accepted: 13 August 2003
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 Jl, Jr and Jlr are solved (to third order). Since Jlr is relevant, the system is mapped on an anisotropic two-channel Kondo problem. The structure of the conductance as a 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 . At even electron occupation, the number of channels equals twice the spin of the triple dot (hence it is a fully screened impurity).
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 72.10.-d – Theory of electronic transport; scattering mechanisms / 72.15.-v – Electronic conduction in metals and alloys
© EDP Sciences, 2003