Showing papers on "Quantum capacitance published in 1996"
TL;DR: In this article, the authors derived a Boltzman-like equation for the partial WDF describing both propagating and non-propagating electron modes in an effective potential generated by the adiabatic QPC.
Abstract: We have calculated the admittance of a two-dimensional quantum point contact (QPC) using a novel variant of the Wigner distribution function (WDF) formalism. In the semiclassical approximation, a Boltzman-like equation is derived for the partial WDF describing both propagating and nonpropagating electron modes in an effective potential generated by the adiabatic QPC. We show that this quantum kinetic approach leads to the well-known stepwise behavior of the real part of the admittance (the conductance), and of the imaginary part of the admittance (the emittance), in agreement with the latest results, which is determined by the number of propagating electron modes. It is shown, that the emittance is sensitive to the geometry of the QPC, and can be controlled by the gate voltage. We established that the emittance has contributions corresponding to both quantum inductance and quantum capacitance. Stepwise oscillations in the quantum inductance are determined by the harmonic mean of the velocities for the propagating modes, whereas the quantum capacitance is a significant mesoscopic manifestation of the non-propagating (reflecting) modes.
6 citations
TL;DR: In this paper, the nanostructure capacitance is analyzed and is shown to consist of three serially connected components; the first one is an extension of the classical capacitance in electrostatics, the second is due to the electronic density of states of the conductor, and the third comes from the electronic charge distribution inside the conductor.
Abstract: The nanostructure capacitance is analyzed and is shown to consist of three serially connected components; the first one is an extension of the classical capacitance in electrostatics, the second is due to the electronic density of states of the conductor, and the third comes from the electronic charge distribution inside the conductor. The latter two are due to the electronic states inside the conductor, and have only the self-capacitance contribution. A diagrammatic expression of the capacitance is given. As an example, the capacitance-voltage curve for the dual gate silicon on insulator (SOI) metal-oxide-semiconductor (MOS) junction is discussed.
3 citations
Journal Article•
TL;DR: In this paper, the low-temperature AC conductance of a one-dimensional electron system with a strong interaction of finite range is calculated by using linear response theory, where the conductance factorizes into parts which depend on the internal properties of the system, and the external probe.
Abstract: The low-temperature AC conductance of a one-dimensional electron system with a strong interaction of finite range is calculated by using linear response theory. The conductance factorizes into parts which depend on the internal properties of the system, and the external probe. For short-range interaction, the result resembles that for non-interacting electrons, but with the zero-frequency limit and the Fermi velocity renormalized by the interaction strength. For strong and long-range interaction, the conductance shows a peak that is related to charge-wave excitations. In this limit, the AC conductance can be simulated by a quantum capacitance and a quantum inductance.
3 citations
Proceedings Article•
01 Sep 1996TL;DR: In this paper, a new model of the gate-to-channel capacitance is proposed including the transmission line effects, not only for strong inversion but also for moderate and weak inversion regimes, which gives a good description of experimental capacitance curves.
Abstract: A new model of the gate-to-channel capacitance is proposed including the transmission line effects, not only for strong inversion but also for moderate and weak inversion regimes, which gives a good description of experimental capacitance curves. This is achieved by expressing the channel conductance in function of the inversion layer concentration. Quantum effects in the distribution of the inversion charge are taken into account by the introduction of a mean centroid, which is related to an effective capacitance area. This effective area is smaller than the real one due to nonuniform, surface conductivity, which is attributed to a random doping distribution giving fluctuations of the surface potential.
1 citations
Posted Content•
TL;DR: In this paper, the authors calculate the admittance of a two-dimensional quantum point contact (QPC) using a Boltzman-like kinetic equation derived for a partial Wigner distribution function in an effective potential.
Abstract: We calculate the admittance of a two-dimensional quantum point contact (QPC) using a Boltzman-like kinetic equation derived for a partial Wigner distribution function in an effective potential We show that this approach leads to the known stepwise behavior of the admittance as a function of the gate voltage The emittance contains both a quantum inductance determined by the harmonic mean of the velocities for the propagating electron modes and a quantum capacitance determined by the reflected modes
1 citations
08 Dec 1996
TL;DR: In this article, the results of low temperature (4.2 K.. 160 K) magneto-capacitance measurements on vertical structures consisting of a large ensemble of InGaAs quantum dots embedded within GaAs are presented.
Abstract: The results of low temperature (4.2 K .. 160 K) magneto-capacitance measurements on vertical structures consisting of a large ensemble of InGaAs quantum dots embedded within GaAs are presented. Series of peaks were observed in the capacitance-voltage (CV) characteristics at liquid helium temperatures. Their attribution to the addition spectrum of 55 nm quantum dot is discussed. The Landau level-like behaviour of CV features in the highest magnetic field confirms our explanation of experimental data.