ISBN 978-3-8439-1533-5

978-3-8439-1533-5, Reihe Physik

Maximilian Köpke
Influence of a Microwave Resonator on a Nearby Quantum Dot

247 Seiten, Dissertation Universität Stuttgart (2014), Softcover, A5

Zusammenfassung / Abstract

This work investigates the influence of a superconducting microwave resonator of the CPW type on a quantum dot situated inside its gap at a maximum of the electric field strength.

The quantum dot is etched into a (Al,Ga)As heterostructure and characterized by electrical transport measurements.

The book includes a concise introduction to the physics of quantum dots and the theory and practice of superconducting microwave resonators. It introduces Pb as a new versatile material for resonator metalization.

Microwaves are seen to cause symmetric current reversal (negative conductivity) at low bias over the quantum dot. This result is shown to be incompatible with the standard theory of photon-assisted tunneling through the leads. An alternative model including intradot transitions is numerically implemented via Master equations and reproduces the data to a fair degree.

Various other measurements with different configurations of dot and resonator complete the investigation.