Bias driven coherent carrier dynamics in a two-dimensional aperiodic potential



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Moura, F. A. B. F., de and Viana, L. P. and Lyra, M. L. and Malyshev, Andrey and Domínguez-Adame Acosta, Francisco (2008) Bias driven coherent carrier dynamics in a two-dimensional aperiodic potential. Physics Letters A, 372 (44). p. 6694. ISSN 0375-9601

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We study the dynamics of an electron wave-packet in a two-dimensional square lattice with an aperiodic site potential in the presence of an external uniform electric field. The aperiodicity is described by epsilon(m) = V cos(pi alpha m(x)(nu x)) cos(pi alpha m(y)(nu y)) at lattice sites (m(x),m(y)), with pi alpha being a rational number, and v(x) and v(y) tunable parameters. controlling the aperiodicity. Using an exact diagonalization procedure and a finite-size scaling analysis, we show that in the weakly aperiodic regime (nu(x), nu(y) < 1), a phase of extended states emerges in the center of the band at zero field giving support to a macroscopic conductivity in the thermodynamic limit. Turning on the field gives rise to Bloch oscillations of the electron wave-packet. The spectral density of these oscillations may display a double peak structure signaling the spatial anisotropy of the potential landscape. The frequency of the oscillations can be understood using a semi-classical approach.

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© 2008 Elsevier B.V. All rights reserved.
Work at Alagoas was supported by CNPq-Rede Nanobioestruturas, CAPES (Brazilian research agencies) and FAPEAL (Alagoas State agency). Work at Madrid was supported by MEC (Project MOSAICO) and BSCH-UCM (Project PR34/07-15916).

Uncontrolled Keywords:Metal-Insulator-Transition, Range Correlated Disorder, Random-Dimer Model, 1d Anderson Model, Mobility Edge, Bloch Oscillations, Electric-Field, Localization, Absence, Superlattices
Subjects:Sciences > Physics > Materials
ID Code:27301
Deposited On:13 Nov 2014 08:34
Last Modified:13 Nov 2014 08:34

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