Eur. Phys. J. B 37, 399-403 (2004)
https://doi.org/10.1140/epjb/e2004-00072-6

Spin filters with Fano dots

¹ Instituto de Física Rosario, CONICET-UNR, Bv. 27 de Febrero 210 bis, 2000 Rosario, Argentina
² Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica, 8400 Bariloche, Argentina
³ Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Strasse 38, 01187 Dresden, Germany
⁴ Physics Department, Columbia University, New York, NY 10027, USA

Corresponding author: ^a torio@ifir.edu.ar

Received: 6 November 2003
Published online: 2 April 2004

Abstract

We compute the zero bias conductance of electrons through a single ballistic channel weakly coupled to a side quantum dot with Coulomb interaction. In contrast to the standard setup which is designed to measure the transport through the dot, the channel conductance reveals Coulomb blockade dips rather then peaks due to the Fano-like backscattering. At zero temperature the Kondo effect leads to the formation of broad valleys of small conductance corresponding to an odd number of electrons on the dot. By applying a magnetic field in the dot region we find two dips corresponding to a total suppression in the conductance of spins up and down separated by an energy of the order of the Coulomb interaction. This provides a possibility of a perfect spin filter.