Admittance of planar two-terminal quantum systems

Wulf, U.; Racec, P. N.; Racec, E. R.

Admittance of planar two-terminal quantum systems

Authors

Wulf, U.

Racec, P. N.

Racec, E. R.

Description

We develop an approach to calculate the admittance of effectively one-dimensional open quantum systems in random phase approximation. The stationary, unperturbed system is described within the Landauer-Büttiker formalism taking into account the Coulomb interaction in the Hartree approximation. The dynamic changes in the effective potential are calculated microscopically from the charge-charge correlation function resulting from the stationary scattering states. We provide explicit RPA-expressions for the quantum admittance. As a first example the case of a quantum capacitor is considered where we can derive a small-frequency expansion for the admittance which lends itself to an experimental testing of the theory. A comparison of the low-frequency expansion with the complete RPA-expression shows that for a quantum capacitor a simple classical equivalent circuit with frequency-independent elements does not describe satisfactorily the quantum-admittance with increasing the frequency.
13 pages, 4 figures