Wannier-Stark ladder in the linear absorption of a random system with scale-free disorder

Abstract

We study numerically the linear optical response of a quasiparticle moving on a one-dimensional disordered lattice in the presence of a linear bias. The random site potential is assumed to be long-range-correlated with a power-law spectral density $S(k)\sim 1/k^{\alpha }$, $\alpha >0$. This type of correlations results in a phase of extended states at the band center, provided $\alpha$ is larger than a critical value ${\alpha }_c$ [F. A. B. F. de Moura and M. L. Lyra, Phys. Rev. Lett. \textbf{81}, 3735 (1998)]. The width of the delocalized phase can be tested by applying an external electric field: Bloch-like oscillations of a quasiparticle wave packet are governed by the two mobility edges, playing now the role of band edges [F. Dom\'ınguez-Adame \emph{et al.}, Phys. Rev. Lett. \textbf{91}, 197402 (2003)]. We demonstrate that the frequency-domain counterpart of these oscillations, the so-called Wannier-Stark ladder, also arises in this system. When the phase of extended states emerges in the system, this ladder turns out to be a comb of doublets, for some range of disorder strength and bias. Linear optical absorption provides a tool to detect this level structure.

8 pages, 6 PostScript figures, to appear in Phys. Rev. B

References in corpus (2)

• Trapping time statistics and efficiency of transport of optical excitations in dendrimers
• Effects of Scale-Free Disorder on the Anderson Metal-Insulator Transition

Cited by in corpus (4)

• Coherent electron dynamics in a two-dimensional random system with mobility edges
• Bias driven coherent carrier dynamics in a two-dimensional aperiodic potential
• Nonmonotonic energy harvesting efficiency in biased exciton chains
• Intraband exciton relaxation in a biased lattice with long-range correlated disorder