Low Temperature Physics: 45, 1032 (2019); https://doi.org/10.1063/1.5121274
Fizika Nizkikh Temperatur: Volume 45, Number 9 (September 2019), p. 1208-1216    ( to contents , go back )

Coulomb effects on thermally induced shuttling of spin-polarized electrons

O.A. Ilinskaya1, A.D. Shkop1, D. Radic2, H.C. Park3, I.V. Krive1,4, R.I. Shekhter5, and M. Jonson5

1B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Nauki Ave., Kharkiv 61103, Ukraine
E-mail: ilinskaya@ilt.kharkov.ua

2Department of Physics, Faculty of Science, University of Zagreb, Bijenicka 32, Zagreb 10000, Croatia

3Center for Theoretical Physics of Complex Systems, Institute for Basic Science (IBS), Daejeon 34051, Republic of Korea
E-mail: hcpark@ibs.re.kr

4Physical Department, V.N. Karazin Kharkiv National University, Kharkiv 61022, Ukraine

5Department of Physics, University of Gothenburg, SE-412 96 Göteborg, Sweden

Received March 25, 2019, published online July 26, 2019

Abstract

A thermally driven single-electron transistor with magnetic leads and a movable central island (a quantum dot) subject to an external magnetic field is considered. The possibility of a mechanical instability caused by magnetic exchange interactions between spin-polarized electrons in this system was studied by the density matrix method. We proved analytically that for noninteracting electrons in the dot there is no such mechanical instability. However, for finite strengths of the Coulomb correlations in the dot we numerically found critical magnetic fields separating regimes of mechanical instability and electron shuttling on the one hand and damped mechanical oscillations on the other. It was shown that thermally induced magnetic shuttling of spin-polarized electrons is a threshold phenomenon, and the dependence of the threshold bias temperature on model parameters was calculated.

Key words: thermally driven single-electron shuttle, magnetic exchange interaction, spin-polarized electrons.

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