Quantum Dot System Exposed to AC Fields

An applied electrical microwave field might cause an enhancement or a reduction of conductance through a quantum dot system, depending on the possible excitation and relaxation mechanism within the quantum dot. © MPI-FKF / M. Köpke

By applying a low-frequency ac voltage between source and drain of a single-electron transistor, a dc current flows between source and drain. The direction of this dc current can be switched from positive to negative by the applied gate voltage as the non-linear current-voltage characteristics of the single-electron transistor is tuned respectively.

Applying microwave fields to a quantum dot system induces electronic excitations in the leads and the quantum dot. Depending on the excitations and relaxation mechanisms within the quantum dot, a complex dynamics evolves leading to enhanced or reduced dc conductance through the quantum dot, continuously exposed to the microwave field.

Publications

Single-electron tunneling transistor as a current rectifier with potential-controlled current polarity
J. Weis, R. Haug, K. von Klitzing, K. Ploog
Semiconductor Science and Technology 10. 877 (1995)

Superconducting Pb as material for coplanar waveguide resonators on GaAs substrates
M. Koepke, J. Weis
Physica C – Supperconductivity and its Applications 506, 143 (2014)

Theses

Influence of a Microwave resonator on a Nearby Quantum Dot
Maximilian Köpke, Dissertation, Universität Stuttgart (2014)