Efeito capacitivo em um sistema de dois pontos quânticos acoplados no regime Kondo

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

22/07/2011

RESUMO

In this work we study a system composed by two quantum dots coupled to each other and one of each coupled to two metallic leads. Theoretically the system is described by a generalized two-impurity Anderson model. In this Hamiltonian we include both intraand inter-site electron-electron interaction, where the former is due to the confinement of electrons in a given quantum dot, while the last results from the proximity effect between the two quantum dots. To properly study the thermodynamic and transport properties of the system we employ the numerical renormalization group method, that allows us to address in a systematic way the low-temperature physics of the system. Some interesting phenomena are expected in this regime, such as, the emergence of screening of the localized moments by the conduction electrons, the so called Kondo effect and the formation of a two-stage Kondo effect, i.e., as the temperature of the system decreases, the spins of each quantum dots is progressively screened at differents temperatures, which allows for the definition of two distinct Kondo temperatures. Due to the inter-dot coulomb interaction, new conducting regimes emerges, resulting from a charging-and-discharging processes as the gate voltage is varied, modifying the physical properties of the system.

ASSUNTO(S)

pontos quânticos efeito kondo bloqueio de coulomb fisica matéria condensada quantum dots kondo effect coulomb blockage

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