Modelo de Anderson com repulsão coulombiana nos níveis que se acoplam com o ponto quântico
Resumo
In this work, a study of the Anderson model is done for the case of a quantum dot between
two electron gases, single-electron transistor (SET), where a Coulombian repulsion term
was added at the orbitals that are directly coupled to the quantum dot. The resulting model
was treated by the Numerical Renormalization Group technique. The thermodynamic
properties of the quantum dot were studied and a preliminary study of the conductance
in the linear response regime as a function of the temperature was done. The change
in the model Hamiltonian made it necessary to compute manually the initial matrices
entering the Numerical Renormalization Group program. In general, the two conduction
bands, corresponding to the electric contacts, can be manipulated so that one of them ends
decoupled from the quantum dot. With the new term added, this decoupling is impossible,
being necessary to reformulate how the conductance is computed. The contribution of
the quantum dot to some thermodynamic properties was calculated and studied, with
emphasis on the behavior of the Kondo temperature. For the study of the conductance, it
was proposed a calculation method that proved very expensive computationally, preventing
us to generate data for the case of coupled bands during the time of the Master of Science.
However, an analysis of the addition of the Coulombian repulsion in the case of uncoupled
bands was done.
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