Biomedical subjects

W G van der Wiel

Publications and source records attributed to W G van der Wiel.

4 recordsLinked to original sources

PubMed2006

Surface-acoustic-wave-induced transport in a double quantum dot.

We report on nonadiabatic transport through a double quantum dot under irradiation of surface acoustic waves generated on chip. At low excitation powers, absorption and emission of single and multiple phonons are observed. At higher power, sequential phonon assisted tunneling processes excite the double dot in a highly nonequilibrium state. The present system is attractive for studying electron-phonon interaction with piezoelectric coupling.

Journal Article↗

PubMed2003

Magnetically induced chessboard pattern in the conductance of a Kondo quantum dot.

We quantitatively describe the main features of the magnetically induced conductance modulation of a Kondo quantum dot-or chessboard pattern-in terms of a constant-interaction double quantum dot model. We show that the analogy with a double dot holds down to remarkably low magnetic fields. The analysis is extended by full 3D spin density functional calculations. Introducing an effective Kondo coupling parameter, the chessboard pattern is self-consistently computed as a function of magnetic field and electron number, which enables us to explain our experimental data quantitatively.

Journal Article↗

PubMed2002

Two-stage Kondo effect in a quantum dot at a high magnetic field.

We report a strong Kondo effect (Kondo temperature approximately 4 K) at high magnetic field in a selective area growth semiconductor quantum dot. The Kondo effect is ascribed to a singlet-triplet transition in the ground state of the dot. At the transition, the low-temperature conductance approaches the unitary limit. Away from the transition, for low bias voltages and temperatures, the conductance is sharply reduced. The observed behavior is compared to predictions for a two-stage Kondo effect in quantum dots coupled to single-channel leads.

Journal Article↗

PubMed2001

Electron cotunneling in a semiconductor quantum dot.

We report transport measurements on a semiconductor quantum dot with a small number of confined electrons. In the Coulomb blockade regime, conduction is dominated by cotunneling processes. These can be either elastic or inelastic, depending on whether they leave the dot in its ground state or drive it into an excited state, respectively. We are able to discriminate between these two contributions and show that inelastic events can occur only if the applied bias exceeds the lowest excitation energy. Implications to energy-level spectroscopy are discussed.

Journal Article↗