Showing papers on "Magnetocapacitance published in 1989"
TL;DR: Comparison with microscopic calculations shows that the observed pronounced modulation of the magnetocapacitance oscillations has the same origin as the novel resistance oscillations recently reported for this system.
Abstract: Magnetocapacitance measurements are performed on a holographically microstructured AlxGa1-xAs-GaAs heterostructure, in order to obtain direct information about the density of states of a periodically modulated two-dimensional electron gas. Comparison with microscopic calculations shows that the observed pronounced modulation of the magnetocapacitance oscillations has the same origin as the novel resistance oscillations recently reported for this system.
50 citations
TL;DR: In this article, the authors measured the magnetocapacitance of highmobility Si-MOSFETs and found that the thermodynamic density of states of 2D electrons in a strong magnetic field and at low temperatures can be negative when energy levels are partially filled.
34 citations
TL;DR: In this paper, the transition from isolated to coupled quantum dots in a lateral surface-superlattice structure in the presence of a perpendicular magnetic field was studied, and the coupling between the dots can be tuned by changing the bias of the grid gate.
Abstract: We have studied the transition from isolated to coupled quantum dots in a lateral surface‐superlattice structure in the presence of a perpendicular magnetic field. The coupling between the dots can be tuned by changing the bias of the grid gate. Our magnetocapacitance measurements reveal three distinct regimes: isolated quantum dots where collective effects are not observed, a tight‐binding regime where the measurement results are sensitive to the rationality of flux quanta per unit cell, and a superlattice regime where commensurability effects between the magnetic orbits and the superlattice periodicity are observed.
32 citations
TL;DR: In this article, a Van der Pauw structure on GaAs/AlGaAs modulation-doped layers was constructed using x-ray nanolithography, evaporation, and liftoff.
Abstract: We have built four‐probe Van der Pauw structures on GaAs/AlGaAs modulation‐doped layers. On top of the 4×4 mm active area we fabricated a 200 nm period Ti/Au Schottky metal grid‐gate using x‐ray nanolithography, evaporation, and liftoff. Electrons traveling from one contact to the other suffer electron back diffraction at specific gate voltages resulting in transconductance oscillations. Magneto‐capacitance measurements indicate two sets of quantum oscillations corresponding to the charge density under and in‐between the Schottky metal lines. Far infrared cyclotron resonance measurements show a shift in the resonance peak as a function of gate bias.
8 citations
2 citations