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Strong-Coupling Diagram Technique for Strong Electron Correlations

  • A. ShermanEmail author
Conference paper
Part of the NATO Science for Peace and Security Series A: Chemistry and Biology book series (NAPSA)

Abstract

Using the strong coupling diagram technique a closed set of equations was derived for the electron Green’s function of the Hubbard model. Spectral functions calculated self-consistently in the two-dimensional t-U model are in qualitative and in some cases quantitative agreement with results of Monte Carlo simulations in a wide range of electron concentrations. For three different initial bands – the semi-elliptical density of states, t-U and t-t′-U models – the Mott transition occurs at very close values of the Hubbard repulsion \(U_{c} \approx \sqrt{3}\varDelta /2\), where Δ is the initial bandwidth. The behavior of the Mott gap with doping and its width at half-filling depend strongly on the value of the next-nearest hopping constant t′.

Notes

Acknowledgements

This work was supported by the research project IUT2-27, the European Regional Development Fund TK114 and the Estonian Scientific Foundation (grant ETF-9371).

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Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.Institute of PhysicsUniversity of TartuTartuEstonia

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