Parallel carbon nanotube quantum dots and their interactions

Abstract

We present quantum transport measurements of interacting parallel quantum dots formed in the strands of a carbon nanotube rope. In this molecular quantum dot system, transport is dominated by one quantum dot, while additional resonances from parallel side dots appear, which exhibit a weak gate coupling. This differential gating effect provides a tunability of the quantum dot system with only one gate electrode and provides control over the carbon nanotube strand that carries the current. By tuning the system to different states, we use quantum transport as a spectroscopic tool to investigate the interdot coupling and show a route to distinguish among various side dots. By comparing the experimental data with master-equation calculations, we identify conditions for the tunneling rates that are required in order to observe different manifestations of the interdot coupling in the transport spectra.

Spin-orbital and spin Kondo effects in parallel coupled quantum dots

“…As the illustrative example of electrodes with singular DOS we discuss carbon nanotubes (CNTs). They exhibit excellent ballistic transport capabilities with mean free paths of order of microns [38,100]. The numerical results are presented for armchair metallic CNT with chiral vector C = (15, 15) (C is written in the basis of unit vectors of graphene [49]).…”

“…We discus how to manipulate the Kondo state by interference conditions in order to reach new device functionality particularly in spintronic applications. Our general discussion based on variants of two-impurity Anderson model that take into account degeneracy and various perturbations is addressed to double dot devices formed in various materials, including GaAs two-dimensional electron gas [2][3][4], semiconductor nanowires [36] and carbon nanotubes [37,38]. Carbon nanotube quantum dots (CNTQDs) are very attractive not only due to the potential applications, but also from cognitive point of view due to high degeneracy of the energy levels leading to the appearance of exotic many body effects of enhanced symmetry.…”

Interaction effects in electric transport through self-assembled molecular monolayers

“…In other mesoscopic systems, U is likely much smaller (U = 0.15−0.4 meV between strands of nanotubes within a nanotube rope was found in recent experiments 22,23 ), but can still dominate the transport physics at low temperatures.…”

Electron-hole interactions in coupled InAs-GaSb quantum dots based on nanowire crystal phase templates

“…[4][5][6] Systems formed by electrostatic gating are generally studied by electrical measurements, whereas self-assembled QDs, which are difficult to access electrically, are almost exclusively investigated by optical techniques. Coupled QDs are typically of the same material due to the complexity involved in the fabrication.…”