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

Article

关键词: T-J MODEL;    ELECTRONIC-STRUCTURE;    C SUPERCONDUCTOR;    CHARGE DYNAMICS;    QUANTUM OSCILLATIONS;    SPECTRAL WEIGHT;    SUM-RULE;    BANDS;    STATE;    HOLE;   

DOI  :  10.1103/PhysRevB.83.205137

来源: SCIE

【 摘 要 】

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 Green's 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 strongly and the spectral function with nonvanishing next-nearest-neighbor hopping in the underdoped region is in good agreement with angle-resolved photoelectron spectroscopy in the cuprates.

【 授权许可】

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