Dynamical density matrix renormalization group study of spin and charge excitations in the four-leg t−t′−J ladder

Abstract

The ground state of the t-t ′ -J ladder with four legs favors a striped charge distribution for the parameters corresponding to hole-doped cuprate superconductors. We investigate the dynamical spin and charge structure factors of the model by using the dynamical density matrix renormalization group (DMRG) and clarify the influence of the stripe on the structure factors. The dynamical charge structure factor along the momentum direction from q = (0, 0) to (π, 0) clearly shows low-energy excitations corresponding to the stripe order in hole doping. On the other hand, the stripe order weakens in electron doping, resulting in fewer low-energy excitations in the charge channel. In the spin channel, we find incommensurate spin excitations near q = (π, π) forming an hourglass behavior in hole doping, while in electron doping we find clearly spin-wave-like dispersions starting from q = (π, π). Along the (0, 0)-(π, 0) direction, the spin excitations are strongly influenced by the stripes in hole doping, resulting in two branches that form a discontinuous behavior in the dispersion. In contrast, the electron-doped systems show a downward shift in energy toward (π, 0). These behaviors along the (0, 0)-(π, 0) direction are qualitatively similar to momentum-dependent spin excitations recently observed by resonant inelastic x-ray scattering experiments in hole-and electron-doped cuprate superconductors.

Theoretical study of the spin and charge dynamics of two-leg ladders as probed by resonant inelastic x-ray scattering

“…In contrast, the excitations at q = (π/a, π/a), shown in Fig. 3(i), have the ubiquitous incommensurate peaks that are also commonly observed in doped ladders and 2D cuprates [66,[70][71][72]. It is interesting to contrast the results for the doped twoleg spin ladder found above with available results in the doped 2D cuprates at the Cu L-edge.…”

Two-hole ground state wavefunction: Non-BCS pairing in a t−J two-leg ladder

“…It implies that the pairing structure may be generally of non-BCS-type in a doped spin system enforced by the no-double-occupancy constraint. Recently, the pairing of holes at finite doping has been clearly found by DMRG in various generalized doped Mott insulators [18][19][20][21][22] . It is thus highly intriguing and motivating to understand the microscopic origin of the hole pairing state in the limit of a two-hole case, which should shed light on the superconducting mechanism and the wavefunction structure at finite doping, which are experimentally relevant.…”

Coexistence of Two Components in Magnetic Excitations of La$_{2-x}$Sr$_x$CuO$_4$ ($x$ = 0.10 and 0.16)

“…Meanwhile, in the La214 system, the origin of entire magnetic excitations are discussed in terms of localized spin and charge stripes because the one-dimensionally aligned spin and charge domains are statically stabilized around x = 1/8. 10) Several theoretical models, including not only the stripe (ladder) model, 11,12) but also the spiral, 13) Lifshitz spin liquid, 14) and Fermi surface nesting models 15,16) have been proposed to reproduce hourglass-shaped excitations. However, owing to the insufficient experimental resolution and the intensity * fujita@imr.tohoku.ac.jp of the neutron beam in earlier measurements, the determination of adequate models from the observed fuzzy spectra was difficult.…”