Article
Symmetry of twoterminal nonlinear electric conduction.
Solid State Physics and The Nanometer Consortium, Lund University, Box 118, S22100 Lund, Sweden.
Physical Review Letters (Impact Factor: 7.73). 02/2004; 92(4):046803. DOI: 10.1103/PhysRevLett.92.046803 Source: PubMed

Article: Is it the boundaries or disorder that dominates electron transport in semiconductor `billiards'?
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ABSTRACT: Semiconductor billiards are often considered as ideal systems for studying dynamical chaos in the quantum mechanical limit. In the traditional picture, once the electron's mean free path, as determined by the mobility, becomes larger than the device, disorder is negligible and electron trajectories are shaped by specular reflection from the billiard walls alone. Experimental insight into the electron dynamics is normally obtained by magnetoconductance measurements. A number of recent experimental studies have shown these measurements to be largely independent of the billiards exact shape, and highly dependent on sampletosample variations in disorder. In this paper, we discuss these more recent findings within the full historical context of work on semiconductor billiards, and offer strong evidence that smallangle scattering at the sub100 nm lengthscale dominates transport in these devices, with important implications for the role these devices can play for experimental tests of ideas in quantum chaos.Fortschritte der Physik 04/2012; 61(23). · 0.98 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We analyze symmetries of spin transport in twoterminal quantum waveguide structures with Rashba spinorbit coupling and magnetic field modulations. Constraints, imposed by the device structure, on the spin polarization of the transmitted electron beam from the waveguide devices are derived. The results are expected to provide accuracy tests for experimental measurements and numerical calculations, as well as guidelines for spinbased device designs.Physical Review Letters 01/2005; 94(24). · 7.73 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate the nonlinear currentvoltage characteristic of mesoscopic conductors and the current generated through rectification of an alternating external bias. To leading order in applied voltages both the nonlinear and the rectified current are quadratic. This current response can be described in terms of second order conductance coefficients and for a generic mesoscopic conductor they fluctuate randomly from sample to sample. Due to Coulomb interactions the symmetry of transport under magnetic field inversion is broken in a twoterminal setup. Therefore, we consider both the symmetric and antisymmetric nonlinear conductances separately. We treat interactions selfconsistently taking into account nearby gates. The nonlinear current is determined by different combinations of second order conductances depending on the way external voltages are varied away from an equilibrium reference point (bias mode). We discuss the role of the bias mode and circuit asymmetry in recent experiments. In a photovoltaic experiment the alternating perturbations are rectified, and the fluctuations of the nonlinear conductance are shown to decrease with frequency. Their asymptotical behavior strongly depends on the bias mode and in general the antisymmetric conductance is suppressed stronger than the symmetric conductance. We next investigate nonlinear transport and rectification in chaotic rings. To this extent we develop a model which combines a chaotic quantum dot and a ballistic arm to enclose an AharonovBohm flux. In the linear twoprobe conductance the phase of the AharonovBohm oscillation is pinned while in nonlinear transport phase rigidity is lost. We discuss the shape of the mesoscopic distribution of the phase and determine the phase fluctuations.Physical review. B, Condensed matter 08/2007; 76(20). · 3.77 Impact Factor
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