Nonanalytic enhancement of the charge transfer from adatom to one-dimensional semiconductor superlattice and optical absorption spectrum

TL;DR

This paper theoretically investigates how Van Hove singularities enhance charge transfer from adatoms to one-dimensional quantum dot superlattices and analyzes the resulting optical absorption spectrum.

Contribution

It reveals a nonanalytic $g^{4/3}$ enhancement of charge transfer rate due to Van Hove singularities and analyzes the optical absorption spectrum considering non-Markovian and Markovian processes.

Findings

Charge transfer decay rate scales as g^{4/3} due to Van Hove singularity.

Optical absorption spectrum reflects both non-Markovian and Markovian dynamics.

Theoretical model captures complex time evolution of adatom states.

Abstract

The charge transfer from an adatom to a semiconductor substrate of one-dimensional quantum dot array is evaluated theoretically. Due to the Van Hove singularity in the density of electron states at the band edges, the charge transfer decay rate is enhanced nonanalytically in terms of the coupling constant $g$ as $g^{4/3}$. The optical absorption spectrum for the ionization of a core level electron of the adatom to the conduction band is also calculated. The reversible non-Markovian process and irreversible Markovian process in the time evolution of the adatom localized state manifest themselves in the absorption spectrum through the branch point and pole contributions, respectively.