Distinct Charge Orders in the Planes and Chains of Ortho-III-OrderedYBa2Cu3O6+δSuperconductors Identified by Resonant Elastic X-ray Scattering

Abstract

Recently, charge density wave (CDW) order in the CuO(2) planes of underdoped YBa(2)Cu(3)O(6+δ) was detected using resonant soft x-ray scattering. An important question remains: is the chain layer responsible for this charge ordering? Here, we explore the energy and polarization dependence of the resonant scattering intensity in a detwinned sample of YBa(2)Cu(3)O(6.75) with ortho-III oxygen ordering in the chain layer. We show that the ortho-III CDW order in the chains is distinct from the CDW order in the planes. The ortho-III structure gives rise to a commensurate superlattice reflection at Q=[0.33 0 L] whose energy and polarization dependence agrees with expectations for oxygen ordering and a spatial modulation of the Cu valence in the chains. Incommensurate peaks at [0.30 0 L] and [0 0.30 L] from the CDW order in the planes are shown to be distinct in Q as well as their temperature, energy, and polarization dependence, and are thus unrelated to the structure of the chain layer. Moreover, the energy dependence of the CDW order in the planes is shown to result from a spatial modulation of energies of the Cu 2p to 3d(x(2)-y(2)) transition, similar to stripe-ordered 214 cuprates.

Comparison of charge modulations in La1.875Ba0.125CuO4and YBaThampy1, Blanco-Canosa2, García-Fernández3 et al. 2013Phys. Rev. BSelf Cite415490View full textAdd to dashboardCite

“…First, the temperature dependence of the charge modulation (not shown here) shows that its correlation length is longest at 60 K, and decreases sharply at lower (25 K) as well as higher (100 K) temperatures. This is distinct from the behavior of the chain order peak, which grows stronger with decreasing temperature with no notable feature at T C [20]. Second, we in fact observed the chain order peak along H in this same sample.…”

Anomalous thermal diffusivity in underdoped YBa 2 Cu 3 O 6+x

“…3 shows the temperature dependence of D −1 with the fit to Eq. 6 above 150 K, where we are free of the interference with the onset of charge order (27,28). Using the known temperaturedependent total heat capacity (23) and electronic specific heat (57) (at RT, c ph ∼ c, whereas ce ∼ 0.014c) and assuming in-plane Fermi velocity found, for example, in angle-resolved photoemission spectroscopy measurements vF ≈ 2.15 × 10 7 cm/s (58), we find (e.g., for YBCO6.75) that, in the Cu-O planes, the prefactor αe ≈ 0.25±0.02 and α ph ≈ 1.64±0.09, whereas along the chains, αe ≈ 0.53 ± 0.02 and α ph ≈ 2.8 ± 0.2.…”

Staggered Flux State in Two-Dimensional Hubbard Models

“…2,20 (3) Charge orders or charge density waves are observed in resonant X-ray scattering experiments. [21][22][23] (4) (π, π)-folded (shadow) bands appear in ARPES spectra, and so forth. [24][25][26][27] Note, however, that the thermodynamic properties such as specific heat and spin susceptibility have not provided any evidence of the phase transition.…”