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Theory of Core-Level Photoemission and the X-ray Edge Singularity Across the Mott Transition

P. S. Cornaglia·A. Georges
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Abstract

The zero temperature core-level photoemission spectrum is studied across the metal to Mott insulator transition using dynamical mean-field theory and Wilson's numerical renormalization group. An asymmetric power-law divergence is obtained in the metallic phase with an exponent alpha(U,Q)-1 which depends on the strength of both the Hubbard interaction U and the core-hole potential Q. For Q <~ U_c/2 alpha decreases with increasing U and vanishes at the transition (U -> U_c) leading to a symmetric peak in the insulating phase. For Q >~ U_c/2, alpha remains finite close to the transition, but the integrated intensity of the power-law vanishes and there is no associated peak in the insulator. The weight and position of the remaining peaks in the spectra can be understood within a molecular orbital approach.

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P. S. Cornaglia, A. Georges. 2007-03-13. Theory of Core-Level Photoemission and the X-ray Edge Singularity Across the Mott Transition. https://doi.org/10.1103/physrevb.75.115112

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