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.


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