2008/09/12 by F. A. B. F. de Moura, Leonardo P. Viana, L. P. Viana +5
Physics and Astronomy · #Quantum and electron transport phenomena #Semiconductor Quantum Structures and Devices #Spectroscopy and Quantum Chemical Studies #cond-mat.dis-nn #cond-mat.mes-hall
paper · pdf · doi:10.1016/j.physleta.2008.09.019
published as Phys. Lett. A 372, 6694 (2008) · 16 pages, to appear in Phys. Lett. A
openalex publication_date 2008/09/12 · arxiv created 2008/09/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 ε\bf m = Vcos(παmxνx)cos(παmyνy) at lattice sites (mx, my), with πα being a rational number, and νx and νy tunable parameters, controlling the aperiodicity. Using an exact diagonalization procedure and a finite-size scaling analysis, we show that in the weakly aperiodic regime (νx,νy < 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.