Spin filtering and thermopower in star coupled quantum dot devices
Abstract
We analyze the linear thermoelectric transport properties of devices with three quantum dots in a star configuration. A central quantum dot is tunnel-coupled to source and drain electrodes and to two additional quantum dots. For a wide range of parameters, in the absence of an external magnetic field, the system is a singular Fermi liquid with a non-analytic behavior of the electric transport properties at low energies. The singular behavior is associated with the development of a ferromagnetic or an underscreened Kondo effect, depending on the parameter regime. A magnetic field drives the system into a regular Fermi liquid regime and leads to a large peak () in the spin thermopower as a function of the temperature, and to a spin polarized current for a wide range of parameters due to interference effects. We find a qualitatively equivalent behavior for systems with a larger number of side coupled quantum dots, with the maximum value of the spin thermopower decreasing as the number of side-coupled quantum dots increases.
Cite
@article{arxiv.1611.03816,
title = {Spin filtering and thermopower in star coupled quantum dot devices},
author = {J. A. Andrade and Pablo S. Cornaglia},
journal= {arXiv preprint arXiv:1611.03816},
year = {2016}
}