2 research outputs found
Suppression of d-wave superconductivity in the checkerboard Hubbard model
Using a dynamical cluster quantum Monte Carlo approximation we investigate
the d-wave superconducting transition temperature in the doped 2D
repulsive Hubbard model with a weak inhomogeneity. The inhomogeneity is
introduced in the hoppings \tp and in the form of a checkerboard pattern
where is the hopping within a plaquette and \tp is the hopping
between the plaquettes. We find inhomogeneity suppresses . The
characteristic spin excitation energy and the strength of d-wave pairing
interaction decrease with decreasing suggesting a strong correlation
between these quantities.Comment: Five pages, four figures. Accepted for Phys. Rev. B (Rapid Com.
Effect of strong correlations on the high energy anomaly in hole- and electron-doped high-Tc superconductors
Recently, angle-resolved photoemission spectroscopy (ARPES) has been used to
highlight an anomalously large band renormalization at high binding energies in
cuprate superconductors: the high energy 'waterfall' or high energy anomaly
(HEA). This paper demonstrates, using a combination of new ARPES measurements
and quantum Monte Carlo simulations, that the HEA is not simply the by-product
of matrix element effects, but rather represents a cross-over from a
quasiparticle band at low binding energies near the Fermi level to valence
bands at higher binding energy, assumed to be of strong oxygen character, in
both hole- and electron-doped cuprates. While photoemission matrix elements
clearly play a role in changing the aesthetic appearance of the band
dispersion, i.e. the 'waterfall'-like behavior, they provide an inadequate
description for the physics that underlies the strong band renormalization
giving rise to the HEA. Model calculations of the single-band Hubbard
Hamiltonian showcase the role played by correlations in the formation of the
HEA and uncover significant differences in the HEA energy scale for hole- and
electron-doped cuprates. In addition, this approach properly captures the
transfer of spectral weight accompanying both hole and electron doping in a
correlated material and provides a unifying description of the HEA across both
sides of the cuprate phase diagram.Comment: Original: 4 pages, 4 figures; Replaced: changed and updated content,
12 pages, 6 figure