Weakly correlated electrons on a square lattice: a renormalization group theory

Дата и время публикации : 1998-12-17T19:04:39Z

Авторы публикации и институты :
D. Zanchi
H. J. Schulz

Ссылка на журнал-издание: Ссылка на журнал-издание не найдена
Коментарии к cтатье: 42 pages, 19 figures included (minor corrections)
Первичная категория: cond-mat.str-el

Все категории : cond-mat.str-el, cond-mat.supr-con

Краткий обзор статьи: We formulate the exact Wilsonian renormalization group for a system of interacting fermions on a lattice. The flow equations for all vertices of the Wilson effective action are expressed in form of the Polchinski equation. We apply this method to the Hubbard model on a square lattice using both zero- and finite- temperature methods. Truncating the effective action at the sixth term in fermionic variables we obtain the one-loop functional renormalization equations for the effective interaction. We find the temperature of the instability Tc^{RG} as function of doping. We calculate furthermore the renormalization of the angle-resolved correlation functions for the superconductivity (SC) and for the antiferromagnetism (AF). The dominant component of the SC correlations is of the type d while the AF fluctuations are of the type s Following the strength of both SC and AF fluctuation along the instability line we obtain the phase diagram. The temperature Tc^{RG} can be identified with the crossover temperature T{co} found in the underdoped regime of the high-temperature superconductors, while in the overdoped regime Tc^{RG} corresponds to the superconducting critical temperature.

Category: Physics