Pseudogap in underdoped cuprates and spin-density-wave fluctuations

Abstract

We analyze fermionic spectral function in the spin-density-wave (SDW) phase of quasi-2D cuprates at small but finite T. We use a non-perturbative approach and sum up infinite series of thermal self-energy terms, keeping at each order nearly-divergent (T/J) |log epsilon| terms, where epsilon is a deviation from a pure two-dimensionality, and neglecting regular T/J corrections. We show that, as SDW order decreases, the spectral function in the antinodal region acquires peak/hump structure: the coherent peak position scales with SDW order parameter, while the incoherent hump remains roughly at the same scale as at T=0 when SDW order is the strongest. We identify the hump with the pseudogap observed in ARPES and argue that the presence of coherent excitations at low energies gives rise to magneto-oscillations in an applied field. We show that the same peak/hump structure appears in the density of states and in optical conductivity.Comment: 14 pages, 12 figures, to be published in PR

Quantum oscillations in the high- T c cuprates

“…-In the second scenario, the antinodal spectral weight is destroyed by a finite-moment density-wave order parameter as suggested in [34,118,77]. In this scenario, it has been proposed [119] that strengthening the spin-density wave order parameter responsible for the pseudo-gap enhances the low-energy coherent excitations, such that the antinodal region evolves into pockets observed by quantum oscillations in an applied magnetic field.…”

Doping-Dependent Photon Scattering Resonance in the Model High-Temperature SuperconductorHgBa2CuO4+δRevealed by Raman Scattering and Optical Ellipsometry

“…8 34), and it has been attributed to a transition from a localized polaronic state inside the charge-transfer gap to an extended state above the gap [35]. Other possibilities, such as a breakdown of the Zhang-Rice singlet approximation at finite doping [36], doped holes not entering the planar orbitals [37], or splitting of the charge-transfer peak with the suppression of AF correlation [38], cannot be ruled out at this time. Band-structure calculations for undoped Hg1201 indicate the presence of a Hg-O band not far from the Fermi level which may further evolve with doping [39], but this scenario would have difficulty explaining the resonance effect on two-magnon excitations given the large spatial separation between the Cu-O and Hg layers.…”

Ground-state phase diagram of the square lattice Hubbard model from density matrix embedding theory

“…In this region, a variety of spin-density [25,43,45,46,49,[83][84][85], charge-density [25,[86][87][88], pair-density wave [88][89][90][91], and stripe orders [30,32,51,52,85,[92][93][94][95] have been posited in both the Hubbard model and the simpler t-J model, with different types of orders seen in different simulation methods. These inhomogeneous phases are proposed to be relevant in the pseudogap physics [89,90,[96][97][98][99][100]. Recent projected entangled pair state (PEPS) studies of the t-J model and Hubbard model at large U 8 suggest that inhomogeneous and homogeneous states are near degenerate at low doping and can be stabilized with small changes in the model parameters [95,101].…”