engleski

High-energy anomalies in covalent high-Tc cuprates with large Hubbard Ud on copper

A large $U_d$ theory is constructed for the metallic state of high-T$_c$ cuprates. The Emery three-band model, extended with Ox-Oy hopping $t_pp$, and with $U_d\rightarrow\infty$, is mapped on slave fermions. The Dyson time-dependent diagrammatic theory in terms of the Cu-O hopping tpd, starting from the nondegenerate unperturbed ground state, is translationally and asymptotically locally gauge invariant. The small parameter of the theory is the average hole occupation of Cu sites $n_d$. The lowest order of the theory generates the single particle propagators of the hybridized $pdp$- and $dpd$-fermions with the exact covalent three band structure. The leading many-body effect is band narrowing, accompanied by Landau-like damping of the single particle propagation, due to incoherent local charge Cu-O fluctuations. The corresponding continuum is found below and above the Fermi level.

Cuprates; Strong correlations; Emery model; Charge fluctuations; Diagrammatic theory; Slave fermions

S.I. on Electronic Crystals (ECRYS-2014) ; Rad je kao pozvano predavanje, uz međunarodnu recenziju prezentiran na skupu International School and Workshop on Electronic Crystals "ECRYS-2014", održanom od 11.-23.08.2014., Cargèse, Francuska.