2008/03/03 by Elena Díaz, E. Díaz, F. Domínguez‐Adame +1
Physics and Astronomy · #Condensed matter physics #Exciton #Exponential decay #Exponential function #Lattice (music) #Physics #Quantum and electron transport phenomena #Quantum mechanics #Relaxation (psychology) #Semiconductor Quantum Structures and Devices #Spectral density #Spectroscopy and Quantum Chemical Studies #cond-mat.dis-nn
paper · pdf · doi:10.1103/physrevb.77.134201
arxiv created 2008/03/03 · openalex publication_date 2008/04/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We numerically study the intraband exciton relaxation in a one-dimensional lattice with a scale-free disorder in the presence of a linear bias. Exciton transport is the incoherent hopping over the eigenstates of the static lattice. The site potential of the unbiased lattice is long-range-correlated with a power-law spectral density S(k)\ensuremath∼1/k^\ensuremathα, \ensuremathα>0. The lattice supports a phase of extended states at the center of the band, provided \ensuremathα is larger than a critical value \ensuremathαc [F. A. B. F. de Moura and M. L. Lyra, Phys. Rev. Lett. 81, 3735 (1998)]. When the bias is applied, the absorption spectrum displays clear signatures of the Wannier--Stark ladder [E. D'\iaz, F. Dom'\inguez-Adame, Yu. A. Kosevich, and V. A. Malyshev, Phys. Rev. B 73, 174210 (2006)]. We demonstrate that in unbiased lattices and in weakly correlated potentials, the decay law is nonexponential. However, the decay is purely exponential when the bias increases and \ensuremathα is large. We relate this exponential decay to the occurrence of the Wannier--Stark ladder in the exciton band.