Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 3: Quantenpunkte und -dr
ähte: Herstellung und Charakterisierung

HL 3.7: Vortrag

Montag, 8. März 2004, 11:45–12:00, H17

Piezoelectric effect on confining potentials of gate-induced quantum wires — •D. Schuster, Ch. Heyn, and W. Hansen — Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany

We investigate a quasi one-dimensional electron gas in a metal-insulator-semiconductor structure on (100) GaAs. The quantum wires are electrostatically induced beneath lithographically defined metal gates on top of the heterostructure. The metal stripes are known to induce a lateral potential via the piezoelectric effect. We investigate quantum wires beneath gates oriented along [010] and [011] directions. The piezoelectric effect is expected to be absent in the case of [010] direction. We employ so-called sidegates to tune the strength of the confinement. We use magneto-capacitance spectroscopy to evaluate the strength of the confinement from subband quantization energies. Surprisingly, we find similar confinements in cristallographically different directions. This is in contrast to our transport measurements on a similar sample where almost no commensurability oscillations are observed in [010] direction.