Eur. Phys. J. B (2014) 87: 12
https://doi.org/10.1140/epjb/e2013-41013-4

Regular Article

The mesoscopic X-ray edge problem: Boundary effects enhance photoabsorption in quantum dots

¹ Institut für Physik, Technische Universität Ilmenau, Weimarer Str. 25, 98693 Ilmenau, Germany
² Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany

^a e-mail: martina.hentschel@tu-ilmenau.de

Received: 26 April 2013
Received in final form: 16 November 2013
Published online: 15 January 2014

Abstract

We investigate the X-ray edge problem and photoabsorption spectra of mesoscopic quantum dot systems, in particular those of rectangular shape. We find strong signatures of Fermi-edge singularities in the photoabsorption cross section that characteristically differ from the well-studied metallic behaviour. The averaged photoabsorption at K-edge, typically rounded in the metallic case, develops a peaked characteristics, comparable to the metallic and mesoscopic L-edge signature, in quantum dots. It stems from the contribution of the system boundary region to the photoabsorption signal and has its origin in the correlation between the single-particle wave functions and their derivatives near a system boundary.