Quantum-chaotic scattering effects in semiconductor microstructures.
We show that classical chaotic scattering has experimentally measurable consequences for the quantum conductance of semiconductor microstructures. These include the existence of conductance fluctuations-a sensitivity of the conductance to either Fermi energy or magnetic field-and weak-localization-a change in the average conductance upon applying a magnetic field. We develop a semiclassical theory and present numerical results for these two effects in which we model the microstructures by billiards attached to leads. We find that the difference between chaotic and regular classical scattering produces a qualitative difference in the fluctuation spectrum and weak-localization lineshape of chaotic and nonchaotic structures. While the semiclassical theory within the diagonal approximation accounts well for the weak-localization lineshape and for the spectrum of the fluctuations, we uncover a surprising failure of the semiclassical diagonal-approximation theory in describing the magnitude of these quantum transport effects.
Baranger
Harold U.
HU
AT&T Bell Laboratories 1D-230, 600 Mountain Avenue, Murray Hill, New Jersey 07974-0636Division de Physique Theorique,(a)) Institut de Physique Nucleaire, F-91406 Orsay Cedex, FranceApplied Physics, Yale University, P.O. Box 208284, New Haven, Connecticut 06520-8284.
Jalabert
Rodolfo A.
RA
Stone
A. Douglas
AD