2026-06-28T04:56:56Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/512332023-08-26T07:06:56Zcom_20.500.14352_14col_20.500.14352_15

Bias driven coherent carrier dynamics in a two-dimensional aperiodic potential Moura, F. A. B. F., de Viana, L. P. Lyra, M. L. Malyshev, Andrey Domínguez-Adame Acosta, Francisco © 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). 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. 2023-06-20T10:47:38Z 2023-06-20T10:47:38Z 2008-10-27 journal article 0375-9601 10.1016/j.physleta.2008.09.019 https://hdl.handle.net/20.500.14352/51233 http://dx.doi.org/10.1016/j.physleta.2008.09.019 http://arxiv.org/abs/0809.3362 http://www.sciencedirect.com eng PR34/07-15916 MOSAICO open access Elsevier