Chaotic dynamics and conductance measurements in microstructures
At low temperatures (T<{approximately}1K), electronic conductance through metallic or semiconductor microstructures commonly exhibits quasirandom fluctuations-for instance as a function of an applied magnetic field-resulting from quantum interference. The random character of these fluctuations does not require disorder in the materials, as such fluctuations are also observed in the ballistic regime, i.e. in devices smaller than the electron mean free path, so that essentially all large-angle scattering occurs as specular reflection from the walls of the device rather than from impurities. In principle, such fluctuations would persist even in the absence of disorder, arising purely from quantum interference of electrons scattering chaotically from the geometrical features of the device. This talk will describe recent experiments measuring conductance fluctuations at millikelvin temperatures in submicron {open_quotes}quantum dots{close_quotes} in the shape of an open circle and stadium billiard. The structures were fabricated from GaAs/AlGaAs heterostructures using precise electron beam lithography. Spectral properties of the observed fluctuations will be discussed in the context of recent semiclassical theories based on quantum chaotic scattering. Both the circle and stadium structures exhibit strong fluctuations, raising the question: what role does chaos play in these experiments?
- OSTI ID:
- 281462
- Report Number(s):
- CONF-9305421-; ISSN 0003-0503; TRN: 96:019386
- Journal Information:
- Bulletin of the American Physical Society, Vol. 38, Issue 3; Conference: 1993 American Physical Society annual meeting on atomic, molecular, and topical physics, Reno, NV (United States), 16-19 May 1993; Other Information: PBD: May 1993
- Country of Publication:
- United States
- Language:
- English
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