arXiv subjects

Rok Zitko

Publications and source records attributed to Rok Zitko.

57 records · Page 4Linked to original sources

arXiv2006

Fermi-liquid versus non-Fermi-liquid behavior in triple quantum dots

We study the effect of electron hopping in triple quantum dots modelled by the three-impurity Anderson model. We determine the range of hopping parameters where the system exhibits the two-channel Kondo effect and has non-Fermi-liquid properties in a wide temperature interval. As this interval is entered from above, the conductance through the side dots increases to a half of the conductance quantum, while the conductance through the system remains small. At lower temperatures the conductance through the system increases to the unitary limit as the system crosses over to the Fermi-liquid ground state. Measuring the differential conductance in a three terminal configuration provides an experimental probe into the NFL behavior.

cond-mat.str-el↗

arXiv2005

Enhanced Conductance Through Side-Coupled Double Quantum Dots

Conductance, on-site and inter-site charge fluctuations and spin correlations in the system of two side-coupled quantum dots are calculated using the Wilson's numerical renormalization group (NRG) technique. We also show spectral density calculated using the density-matrix NRG, which for some parameter ranges remedies inconsistencies of the conventional approach. By changing the gate voltage and the inter-dot tunneling rate, the system can be tuned to a non-conducting spin-singlet state, the usual Kondo regime with odd number of electrons occupying the dots, the two-stage Kondo regime with two electrons, or a valence-fluctuating state associated with a Fano resonance. Analytical expressions for the width of the Kondo regime and the Kondo temperature are given. We also study the effect of unequal gate voltages and the stability of the two-stage Kondo effect with respect to such perturbations.

cond-mat.mes-hall↗

arXiv2002

Tunneling through an Aharonov-Bohm ring -- effects of dephasing by electron-electron interactions

We develop a non-perturbative numerical method to study a single electron tunneling through an Aharonov-Bohm ring in the presence of bound, interacting electrons. Inelastic processes and spin-flip scattering are properly taken into account. We show that electron-electron interactions described by the Hubbard Hamiltonian lead to strong dephasing and we obtain high transmission probability at Phi=pi even at small interaction strength. Depending on the many-electron state on the ring, dephasing can occur in elastic or inelastic channels with or without changing the spin of the scattering electron.

cond-mat.str-el↗