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arXiv · 0809.3362

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

F. A. B. F. de Moura·L. P. Viana·M. L. Lyra·V. A. Malyshev·F. Dominguez-Adame
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Abstract

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 $ε_{\bf m} = V\cos{(παm_x^{ν_x})}\cos{(παm_y^{ν_y})}$ at lattice sites $(m_x, m_y)$, with $πα$ being a rational number, and $ν_x$ and $ν_y$ tunable parameters, controlling the aperiodicity. Using an exact diagonalization procedure and a finite-size scaling analysis, we show that in the weakly aperiodic regime ($ν_x,ν_y < 1$), 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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BibTeXRIS

F. A. B. F. de Moura, L. P. Viana, M. L. Lyra, V. A. Malyshev, F. Dominguez-Adame. 2008-09-19. Bias driven coherent carrier dynamics in a two-dimensional aperiodic potential. https://doi.org/10.1016/j.physleta.2008.09.019

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