Theory of electronic properties and quantum spin blockade in a gated linear triple quantum dot with one electron spin each

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DOIResolve DOI: http://doi.org/10.1103/PhysRevB.85.085309
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TypeArticle
Journal titlePhysical Review B - Condensed Matter and Materials Physics
ISSN1098-0121
Volume85
Issue8
Article number85309
AbstractWe present a theory of electronic properties and the spin-blockade phenomena in a gated linear triple quantum dot. Quadruple points where four different charge configurations are on resonance, particularly involving (1,1,1) configuration, are considered. In the symmetric case, the central dot is biased to higher energy and a single electron tunnels through the device when the (1,1,1) configuration is resonant with (1,0,1), (2,0,1), (1,0,2) configurations. The electronic properties of a triple quantum dot are described by a Hubbard model containing two orbitals in the two unbiased dots and a single orbital in the biased dot. The transport through the triple-quantum-dot molecule involves both singly and doubly occupied configurations and necessitates the description of the (1,1,1) configuration beyond the Heisenberg model. Exact eigenstates of the triple-quantum-dot molecule with up to three electrons are used to compute current assuming weak coupling to the leads and nonequilibrium occupation of quantum molecule states obtained from the rate equation. The intramolecular relaxation processes due to acoustic phonons and cotunneling with the leads are included, and are shown to play a crucial role in the spin-blockade effect. We find a quantum-interference-based spin-blockade phenomenon at low source-drain bias and a distinct spin blockade due to a trap state at higher bias. We also show that, for an asymmetric quadruple point with (0,1,1), (1,1,1,), (0,2,1), (0,1,2) configurations on resonance, the spin blockade is analogous to the spin blockade in a double quantum dot. ©2012 American Physical Society.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Institute for Microstructural Sciences (IMS-ISM)
Peer reviewedYes
NPARC number21269241
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Record identifier22e777d0-6c07-4ae7-be3f-1390ec29e894
Record created2013-12-12
Record modified2016-05-09
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