Martin Sigrist

Spatially Resolved Manipulation of Single Electrons in Quantum Dots Using a Scanned Probe

The scanning metallic tip of a scanning force microscope was coupled capacitively to electrons confined in a lithographically defined gate-tunable quantum dot at a temperature of 300 mK. Single electrons were made to hop on or off the dot by moving the tip or by changing the tip bias voltage owing to the Coulomb-blockade effect. Spatial images of conductance resonances map the interaction potential between the tip and individual electronic quantum dot states. Under certain conditions this interaction is found to contain a tip-voltage induced and a tip-voltage-independent contribution.

Analytic model of the energy spectrum of a graphene quantum dot in a perpendicular magnetic field

We analytically calculate the energy spectrum of a circular graphene quantum dot with radius

Fano effect in a quantum-ring–quantum-dot system with tunable coupling

R

Magnetic-field-dependent transmission phase of a double-dot system in a quantum ring.

subjected to a perpendicular magnetic field

Coherent Probing of Excited Quantum Dot States in an Interferometer

B

Phase coherence in the inelastic cotunneling regime.

by applying the infinite-mass boundary condition. We can retrieve well-known limits for the cases

Electronic properties of antidot lattices fabricated by atomic force lithography

R,B\ensuremath{\rightarrow}\ensuremath{\infty}

Time-reversal symmetry breaking and spontaneous currents in s-wave/normal-metal/d-wave superconductor sandwiches

and

Interference in a quantum dot molecule embedded in a ring interferometer

B\ensuremath{\rightarrow}0

A Radio Frequency Quantum Point Contact Charge Read‐Out

. Our model is capable of capturing the essential details of recent experiments. Quantitative agreement between theory and experiment is limited due to the fact that a circular dot deviates from the actual experimental geometry, that disorder plays a significant role, and that interaction effects may be relevant.