Publications (46) View all
-
Article: Magnetic excitations in stripe-ordered La$_{1.875}$Ba$_{0.125}$CuO$_4$ studied using resonant inelastic x-ray scattering
[show abstract] [hide abstract]
ABSTRACT: The charge and spin correlations in La$_{1.875}$Ba$_{0.125}$CuO$_4$ (LBCO 1/8) are studied using Cu $L_3$ edge resonant inelastic x-ray scattering (RIXS). The static charge order (CO) is observed at a wavevector of $(0.24,0)$ and its charge nature confirmed by measuring the dependence of this peak on the incident x-ray polarization. The paramagnon excitation in LBCO 1/8 is then measured as it disperses through the CO wavevector. Within the experimental uncertainty no changes are observed in the paramagnon due to the static CO, and the paramagnon seems to be similar to that measured in other cuprates, which have no static CO. Given that the stripe correlation modulates both the charge and spin degrees of freedom, it is likely that subtle changes do occur in the paramagnon due to CO. Consequently, we propose that future RIXS measurements, realized with higher energy resolution and sensitivity, should be performed to test for these effects.05/2013; -
Dataset: Science 337 821 fluctuatingCDWinYBCO 2012 SUPPLEMENTARY
-
Dataset: aarXiv 1212.5580 (Blanco-Canosa three phase competition in YBCO)
-
Article: Momentum-dependent charge correlations in YBa$_2$Cu$_3$O$_{6+\delta}$ superconductors probed by resonant x-ray scattering: Evidence for three competing phases
[show abstract] [hide abstract]
ABSTRACT: We have used resonant x-ray scattering to determine the momentum dependent charge correlations in YBa$_2$Cu$_3$O$_{6.55}$ samples with highly ordered chain arrays of oxygen acceptors (ortho-II structure). The results reveal nearly critical, biaxial charge density wave (CDW) correlations at in-plane wave vectors (0.315, 0) and (0, 0.325). The corresponding scattering intensity exhibits a strong uniaxial anisotropy. The CDW amplitude and correlation length are enhanced as superconductivity is weakened by an external magnetic field. Analogous experiments were carried out on a YBa$_2$Cu$_3$O$_{6.6}$ crystal with a dilute concentration of spinless (Zn) impurities, which had earlier been shown to nucleate incommensurate magnetic order. Compared to pristine crystals with the same doping level, the CDW amplitude and correlation length were found to be strongly reduced. These results indicate a three-phase competition between spin-modulated, charge-modulated, and superconducting states in underdoped YBa$_2$Cu$_3$O$_{6+\delta}$.12/2012; -
Article: Distinct Charge Orders in the Planes and Chains of Ortho-III-Ordered YBa_{2}Cu_{3}O_{6+δ} Superconductors Identified by Resonant Elastic X-ray Scattering.
[show abstract] [hide abstract]
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.Physical Review Letters 10/2012; 109(16):167001. · 7.37 Impact Factor
