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Many-Impurity Effects in Fourier Transform Scanning Tunneling Spectroscopy

O. Kodra·W. A. Atkinson
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Abstract

Fourier transform scanning tunneling spectroscopy (FTSTS) is a useful technique for extracting details of the momentum-resolved electronic band structure from inhomogeneities in the local density of states due to disorder-related quasiparticle scattering. To a large extent, current understanding of FTSTS is based on models of Friedel oscillations near isolated impurities. Here, a framework for understanding many-impurity effects is developed based on a systematic treatment of the variance Delta rho^2(q,omega) of the Fourier transformed local density of states rho(q,ω). One important consequence of this work is a demonstration that the poor signal-to-noise ratio inherent in rho(q,omega) due to randomness in impurity positions can be eliminated by configuration averaging Delta rho^2(q,omega). Furthermore, we develop a diagrammatic perturbation theory for Delta rho^2(q,omega) and show that an important bulk quantity, the mean-free-path, can be extracted from FTSTS experiments.

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O. Kodra, W. A. Atkinson. 2005-11-07. Many-Impurity Effects in Fourier Transform Scanning Tunneling Spectroscopy. https://doi.org/10.1103/physrevb.73.045404

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