Geometry, chirality, topology and electron-electron interactions in the quadruple quantum dot molecule
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- 作者：Isil Ozfidan ; Anna H. Trojnar ; Marek Korkusinski ; Pawel Hawrylak
- 关键词：A. Nanostructures ; D. Electron&ndash ; electron interactions ; D. Electronic transport
- 刊名：Solid State Communications
- 出版年：2013
- 出版时间：October, 2013
- 年：2013
- 卷：172
- 期：Complete
- 页码：15-19
- 全文大小：447 K
文摘
We present a theory of electronic properties of a quadruple quantum dot molecule (QQD) which focuses on geometry, chirality, and electron-electron interactions. The QQD is described by the extended Hubbard model solved using exact diagonalization method in real and Fourier space. The energy spectrum of a QQD is analysed as a function of the number of electrons Ne, for ring, linear, or star geometry. We discuss the interplay of chirality, topology, and Fermi statistics for a half-filled ring QQD charged with either additional electron or hole. We show that the chirality leads to the appearance of a topological phase and an effective gauge field stabilizing the spin polarised state. The spin polarised state with extra electron (hole) and spin unpolarised state at half-filling lead to spin blockade in transport through the ring-like QQD but not through a linear nor star QQD molecule. We demonstrate that the ground state can be tuned between a total spin S=1/2 and S=3/2 by changing the strength of on-site interactions or tuning the tunnelling matrix element.