Gate-Defined Quantum Dots on Carbon Nanotubes

Quantum dots in carbon nanotubes

In this overview paper, we present low-temperature electronic transport measurements of carbon nanotube quantum dots with a back gate. In a semiconducting tube, charge carriers could be completely depleted. The addition energy and the excitation spectrum have been studied as a function of the number of charges (electrons or holes), one by one. We observe electron–hole symmetry, which is a direc...

Multiwall carbon nanotubes as quantum dots.

We have measured the differential conductance of individual multiwall carbon nanotubes. Coulomb blockade and energy level quantization are observed. The electron levels are nearly fourfold degenerate (including spin) and their evolution in magnetic field (Zeeman splitting) agrees with a g factor of 2. In zero magnetic field the sequential filling of states evolves with spin S according to S = 0...

Double Quantum Dots in Carbon Nanotubes

Nanofabrication of gate-defined GaAs/AlGaAs lateral quantum dots.

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and entanglement, to solve certain problems exponentially faster than with the best known algorithms on a classical computer. Gate-defined lateral quantum dots on GaAs/AlGaAs are one of many avenues explored for the implementation of a qubit. When properly ...

Gate-defined coupled quantum dots in topological insulators

We consider electrostatically coupled quantum dots in topological insulators, otherwise confined and gapped by a magnetic texture. By numerically solving the (2+ 1) Dirac equation for the wave packet dynamics, we extract the energy spectrum of the coupled dots as a function of bias-controlled coupling and an external perpendicular magnetic field. We show that the tunneling energy can be control...