Fermi edge singularities in the mesoscopic regime: Photoabsorption spectra

Article

关键词: X-RAY-ABSORPTION;    GOLDEN-RULE APPROACH;    SIMPLE METALS;    ENERGY-LEVELS;    EMISSION;    SYSTEMS;    ELECTRON;   

DOI  :  10.1103/PhysRevB.76.245419

来源: SCIE

【 摘 要 】

We study Fermi edge singularities in photoabsorption spectra of generic mesoscopic systems such as quantum dots or nanoparticles. We predict deviations from macroscopic-metallic behavior and propose experimental setups for the observation of these effects. The theory is based on the model of a localized, or rank one, perturbation caused by the (core) hole left behind after the photoexcitation of an electron into the conduction band. The photoabsorption spectra result from the competition between two many-body responses, Anderson's orthogonality catastrophe and the Mahan-Nozieres-DeDominicis contribution. Both mechanisms depend on the system size through the number of particles and, more importantly, fluctuations produced by the coherence characteristic of mesoscopic samples. The latter lead to a modification of the dipole matrix element and trigger one of our key results: a rounded K-edge typically found in metals will turn into a (slightly) peaked edge on average in the mesoscopic regime. We consider in detail the effect of the bound state produced by the core hole.

【 授权许可】

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