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arXiv · 1101.4870

Self-energy and Fermi surface of the 2-dimensional Hubbard model

R. Eder·K. Seki·Y. Ohta
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Abstract

We present an exact diagonalization study of the self-energy of the two-dimensional Hubbard model. To increase the range of available cluster sizes we use a corrected t-J model to compute approximate Greens functions for the Hubbard model. This allows to obtain spectra for clusters with 18 and 20 sites. The self-energy has several `bands' of poles with strong dispersion and extended incoherent continua with k-dependent intensity. We fit the self-energy by a minimal model and use this to extrapolate the cluster results to the infinite lattice. The resulting Fermi surface shows a transition from hole pockets in the underdoped regime to a large Fermi surface in the overdoped regime. We demonstrate that hole pockets can be completely consistent with the Luttinger theorem. Introduction of next-nearest neighbor hopping changes the self-energy stronlgy and the spectral function with nonvanishing next-nearest-neighbor hopping in the underdoped region is in good agreement with angle resolved photoelectron spectroscopy.

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R. Eder, K. Seki, Y. Ohta. 2011-01-25. Self-energy and Fermi surface of the 2-dimensional Hubbard model. https://doi.org/10.1103/physrevb.83.205137

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