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artículo con referato
"Scaling of conductance through quantum dots with magnetic field"
I.J. Hamad, C. Gazza, J.A. Andrade, A.A. Aligia, P.S. Cornaglia and P. Roura-Bas
Phys. Rev. B 92(19) (2015) 195113/1-9
Using different techniques, and Fermi-liquid relationships, we calculate the variation with the applied magnetic field (up to second order) of the zero-temperature equilibrium conductance through a quantum dot described by the impurity Anderson model. We focus on the strong-coupling limit U ≫ Δ, where U is the Coulomb repulsion and Δ is half the resonant-level width, and consider several values of the dot level energy Ed, ranging from the Kondo regime εF - Ed ≫ Δ to the intermediate-valence regime εF - EdΔ, where εF is the Fermi energy. We have mainly used the density-matrix renormalization group (DMRG) and the numerical renormalization group (NRG) combined with renormalized perturbation theory (RPT). Results for the dot occupancy and magnetic susceptibility from the DMRG and NRG+RPT are compared with the corresponding Bethe ansatz results for U ∞, showing an excellent agreement once Ed is renormalized by a constant Haldane shift. For U < 3Δ a simple perturbative approach in U agrees very well with the other methods. The conductance decreases with the applied magnetic field for dot occupancies nd 1 and increases for nd 0.5 or nd 1.5 regardless of the value of U. We also relate the energy scale for the magnetic-field dependence of the conductance with the width of the low-energy peak in the spectral density of the dot.
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