Static charge-density-wave (CDW) and spin-density-wave (SDW) order has been convincingly observed in La-based cuprates for some time. However, more recently it has been suggested by quantum oscillation, transport, and thermodynamic measurements that density-wave order is generic to underdoped cuprates and plays a significant role in YBa2Cu3O 6+δ (YBCO). We use resonant soft x-ray scattering at the Cu L and O K edges to search for evidence of density-wave order in ortho-II and ortho-VIII oxygen-ordered YBCO.

We explain that part of the reduction in the parameter uncertainties in the computations of Apgar et al. (Mol. Biosyst. 2010, 6, 1890-900) is due to a greatly increased number of effective data points. © The Royal Society of Chemistry 2011.

Graphene presents many distinctive optical properties that complement its attractive electronic and mechanical characteristics. We review some of the recent progress in understanding the electronic transitions and ultrafast dynamics in single and few-layer graphene crystals. © 2011 AOS.

For reduced gate leakage and enhanced device performance, many IC manufacturers utilize novel metal gate technologies instead of traditional poly silicon gates. The new materials and geometries required to form metal gates mean that new parameters control the optimization of device performance [1]. Traditional gate process control has relied heavily on scatterometry for ensuring that variation in structural dimensions remain in control, as some dimensional deviations can strongly affect device performance.

We study the coexisting smectic modulations and intra-unit-cell nematicity in the pseudogap states of underdoped Bi 2Sr 2CaCu 2O 8+δ. By visualizing their spatial components separately, we identified 2π topological defects throughout the phase-fluctuating smectic states. Imaging the locations of large numbers of these topological defects simultaneously with the fluctuations in the intra-unit-cell nematicity revealed strong empirical evidence for a coupling between them.

The Nernst coefficient of the cuprate superconductor YBa2Cu 3Oy was recently shown to become strongly anisotropic within the basal plane when cooled below the pseudogap temperature T, revealing that the pseudogap phase breaks the fourfold rotational symmetry of the CuO 2 planes. Here we report on the evolution of this Nernst anisotropy at low temperature, once superconductivity is suppressed by a magnetic field. We find that the anisotropy drops rapidly below 80 K, to vanish in the T=0 limit.

We describe how rescaling experimental data obtained from cold atom density profiles can reveal signatures of quantum criticality. We identify a number of important questions which can be answered by analyzing experimental data in this manner. We show that such experiments can distinguish different universality classes and that the signatures are robust against temperature, noise, and finite system size. © 2011 American Physical Society.

We describe the design, construction, and performance of a 4-circle in-vacuum diffractometer for resonant elastic soft x-ray scattering. The diffractometer, installed on the resonant elastic and inelastic x-ray scattering beamline at the Canadian Light Source, includes 9 in-vacuum motions driven by in-vacuum stepper motors and operates in ultra-high vacuum at base pressure of 2 × 10-10 Torr. Cooling to a base temperature of 18 K is provided with a closed-cycle cryostat.

X-ray transparent crystallization plates based upon a novel drop-pinning technology provide a flexible, simple and inexpensive approach to protein crystallization and screening. The plates consist of open cells sealed top and bottom by thin optically, UV and X-ray transparent films. The plates do not need wells or depressions to contain liquids. Instead, protein drops and reservoir solution are held in place by rings with micrometre dimensions that are patterned onto the bottom film.

DNA experiences torsional stress resulting from the activities of motor enzymes and bound proteins. The mechanisms by which this torsional stress is dissipated to maintain DNA structural integrity are not fully known. Here, we show that a Holliday junction can limit torsion by coupling rotation to translocation and torque to force. The torque required to mechanically migrate through individual junctions was found to be an order of magnitude smaller than that required to melt DNA.