Quantum chaos in GaAs/AlxGa1-xAs microstructures

We review clear signatures of "quantum chaos" observable in both open and closed systems realized in GaAs/AlxGa1-xAs microstructures. In open ballistic billiards where scattering dynamics determine the characteristics of quantum transport, we find a striking difference in the shape of the negative magneto-resistance peak for transport through chaotic, stadium cavities-Lorentzian line shape, versus non-chaotic, circle cavities-unusual triangular line shape. In a nearly closed system of individual quantum dot single-electron-transistors, the distribution of the height of Coulomb blockade conductance peaks is strongly non-Gaussian and sensitive to the absence or presence of a magnetic field. Even though our findings are in substantial agreement with the prediction of Random Matrix Theory, there exist evidence that deviations can occur due to the effect of electron-electron interaction. Lastly, we briefly summarize recent observations of pairing effect in ultra-small quantum dots associated with the spin degree of freedom.

Duke Scholars

Author Albert M. Chang Physics