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arXiv · 0909.2401

Quantum Transport in Ladder-Type Networks: Role of nonlinearity, topology and spin

K. Nakamura·D. Matrasulov·G. Milibaeva·J. Yusupov·U. Salomov·T. Ohta·M. Miyamoto
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Abstract

We investigate quantum transport of electrons, phase solitons, etc. through mesoscopic networks of zero-dimensional quantum dots. Straight and circular ladders are chosen as networks with each coupled with three semi-infinite leads (with one incoming and the other two outgoing). Two transmission probabilities (TPs) as a function of the incident energy $ε$ show a transition from anti-phase aperiodic to degenerate periodic spectra at the critical energy $ε_c$ which is determined by a bifurcation point of the bulk energy dispersions. TPs of the circular ladder depend only on the parity of the winding number. Introduction of a single missing bond (MB) or missing step doubles the period of the periodic spectra at $ε>ε_c$ . Shift of the MB by lattice constant results in a striking switching effect at $ε<ε_c$. In the presence of the electric-field induced spin-orbit interaction (SOI), an obvious spin filtering occurs against the spin-unpolarized injection. Against the spin-polarized injection, on the other hand, the spin transport shows spin-flip (magnetization reversal) oscillations with respect to SOI. We also show a role of soliton in the context of its transport through the ladder networks.

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K. Nakamura, D. Matrasulov, G. Milibaeva, J. Yusupov, U. Salomov, T. Ohta, M. Miyamoto. 2009-09-13. Quantum Transport in Ladder-Type Networks: Role of nonlinearity, topology and spin. https://doi.org/10.1088/1751-8113%2F43%2F14%2F145101

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