Admittance of a one-dimensional double-barrier resonant tunneling nanostructure
Shangguan, Wang Zuo
Au Yeung, Tin Cheung
Yu, Ya Bin
Kam, Chan Hin
Date of Issue2002
School of Electrical and Electronic Engineering
We study the dynamic response of a one-dimensional double-barrier nanostructure to an ac bias. Combining the Schrödinger equation, Poisson equation and the scattering theory, we calculate the internal potential, charge density, and the ac conductance as well. The results show that the charge distribution is antisymmetric with respect to the center of the double barrier, and depends crucially on the relative position of the Fermi level to the resonant energies of the well. The diagonal emittance is found to have a similar dependence. It is negative (inductive behavior) when the Fermi energy is very close to the resonant energies, and it reaches the negative maximum at resonant energies, while it is always positive (capacitive behavior) when the Fermi energy is within the barrier depth and far from resonance, and develops two peaks closely on both sides of the inductive peak. This result is in agreement with that obtained from discrete model. In addition, we find that the capacitive peaks correspond to the maxima of charge-density fluctuation, and inductive peaks to zero charge-density distribution. Therefore, the sign and magnitude of emittance reflect how the charge piles up inside the device.
Physical Review B - Condensed Matter and Materials Physics
© 2002 American Physical Society (APS). This paper was published in Physical Review B - Condensed Matter and Materials Physics and is made available as an electronic reprint (preprint) with permission of American Physical Society (APS). The published version is available at: [doi:http://dx.doi.org/10.1103/PhysRevB.65.235315]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.