Stuttgart 2012 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 35: Poster 2

Q 35.8: Poster

Mittwoch, 14. März 2012, 16:30–19:00, Poster.I+II

Perfect conducting channel in two-dimensional random lattices with XY-disorder and engineered hopping amplitudes — •Alberto Rodriguez1, Arunava Chakrabarti2, and Rudolf A. Römer31Phisikalisches Institut, Albert-Ludwigs Universität Freiburg, Hermann-Herder Strasse 3, D-79104, Freiburg, Germany — 2Department of Physics, University of Kalyani, Kalyani, West Bengal-741 235, India — 3Department of Physics and Centre for Scientific Computing, University of Warwick, Coventry, CV4 7AL, United Kingdom

We study the spectral and transport properties of two-dimensional lattices with random on-site energies єx,y, and random vertical hopping amplitudes γ(x,y)→ (x,y+1). The disorder in the system is defined by three independent random sequences {αx}, {βy}, {ξy}, in the following way: єx,yxβy, and γ(x,y)→ (x,y+1)xξy. By engineering the random distribution ξy, a full band of Bloch states emerges in the spectrum, and a perfect conducting channel in the x direction is induced in the system. We describe how to create the conductance channel in finite systems, and we study its robustness against deviations from the ideal requested values for ξy. Remarkably, we demonstrate that the channel persists in the thermodynamic limit —for the infinite two-dimensional system—. Furthermore, we also discuss how to modify the localization of the eigenstates almost at will in the x and y directions. Our results are constructed analytically and supported by extensive numerical calculations of localization lengths, conductance and density of states.

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