Gate-voltage dependence of Kondo effect in a triangular quantum dot

Abstract

We study the conductance through a triangular triple quantum dot, which are connected to two noninteracting leads, using the numerical renormalization group (NRG). It is found that the system shows a variety of Kondo effects depending on the filling of the triangle. The SU(4) Kondo effect occurs at half-filling, and a sharp conductance dip due to a phase lapse appears in the gate-voltage dependence. Furthermore, when four electrons occupy the three sites on average, a local S=1 moment, which is caused by the Nagaoka mechanism, is induced along the triangle. The temperature dependence of the entropy and spin susceptibility of the triangle shows that this moment is screened by the conduction electrons via two separate stages at different temperatures. The two-terminal and four-terminal conductances show a clear difference at the gate voltages, where the SU(4) or the S=1 Kondo effects occurring.

4 pages, 4 figs: typos just below (4) are corrected, results are not affected

References in corpus (5)

• Magnetically Tunable Kondo - Aharonov-Bohm Effect in a Triangular Quantum Dot
• Numerical renormalization group approach to a quartet quantum-dot array connected to reservoirs:gate-voltage dependence of the conductance
• Determination of the phase shifts for interacting electrons connected to reservoirs
• NRG approach to the transport through a finite Hubbard chain connected to reservoirs
• Kondo screening of a high-spin Nagaoka state in a triangular quantum dot

Cited by in corpus (4)

• Kondo effects in a triangular triple quantum dot: NRG study in the whole region of the electron filling
• Kondo regime in triangular arrangements of quantum dots: Molecular orbitals, interference and contact effects
• Kondo effects in a triangular triple quantum dot with lower symmetries
• Multistage Kondo effect in a multiterminal geometry: A modular quantum interferometer