Perfect thermal spin filter and pure spin thermoelectric generator based on a laterally coupled double quantum-dot array

¹ Department of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology - Wuhan 430074, PRC
² China Center of Advanced Science and Technology (CCAST) - Beijing 100080, PRC

^(a) hhfu@hust.edu.cn

Received: 13 March 2013
Accepted: 2 September 2013

Abstract

We report a proposal to realize a perfect thermal spin filter and a pure spin thermoelectric generator based on a laterally coupled double quantum-dot (DQD) array. It is found that the thermal conductance spectrum of the system presents a well-defined adiabatic band with very steep edges due to Fano antiresonance. Considering a Zeeman splitting, highly to 100% thermospin-polarized windows appear in the spin-splitting thermal conductance, which makes this DQD array applicable as a perfect thermal spin filter. Moreover, under some appropriate conditions, the charge thermopower is zero while the spin thermopower is not, indicating it can be used as a pure spin thermoelectric generator. More important, to achieve these thermoelectric characteristics, the DQD array does not need a very large chain length.