We describe a hybrid pixel array detector (electron microscope pixel array detector, or EMPAD) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128×128 pixel detector consists of a 500 μm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit. The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity.

The properties of two-dimensional transition metal dichalcogenides arising from strong spin-orbit interactions and valley-dependent Berry curvature effects have recently attracted considerable interest. Although single-particle and excitonic phenomena related to spin-valley coupling have been extensively studied, the effects of spin-valley coupling on collective quantum phenomena remain less well understood.

High-pressure cryocooling (HPC) has been developed as a technique for reducing the damage that frequently occurs when macromolecular crystals are cryocooled at ambient pressure. Crystals are typically pressurized at around 200 MPa and then cooled to liquid nitrogen temperature under pressure; this process reduces the need for penetrating cryoprotectants, as well as the damage due to cryocooling, but does not improve the diffraction quality of the as-grown crystals.

The surface photovoltage (SPV) characteristics of periodic nanopillar (NP) arrays formed on Si wafers were investigated. The NP arrays exhibited broadband omnidirectional antireflection effects with Mie resonance. Kelvin probe force microscopy (KPFM) revealed that the positive fixed charges in SiNx layers induced band bending at the Si surface and increased surface photovoltage (SPV) at the NP top surface. Estimated SPV values, determined by the amount of surface band bending, were similar in NPs and planar counterparts.

We calculate how correlations in a Bose lattice gas grow during a finite-speed ramp from the Mott to the superfluid regime. We use an interacting doublon-holon model, applying a mean-field approach for implementing hard-core constraints between these degrees of freedom. Our solutions are valid in any dimension and agree with experimental results and with density matrix renormalization group calculations in one dimension. We find that the final energy density of the system drops quickly with increased ramp time for ramps shorter than one hopping time, JÏ„ramp1.

We demonstrate that the electronic band structure extracted from quasiparticle interference spectroscopy [Nat. Phys. 9, 468 (2013)1745-247310.1038/nphys2671] and the theoretically computed form of the superconducting gaps [Proc. Natl. Acad. Sci. USA 111, 11663 (2014)PNASA60027-842410.1073/pnas.1409444111] can be used to understand the dI/dV line shape measured in the normal and superconducting state of CeCoIn5 [Nat. Phys. 9, 474 (2013)1745-247310.1038/nphys2672].

The peculiar features of quantum magnetism sometimes forbid the existence of gapped "featureless" paramagnets which are fully symmetric and unfractionalized. The Lieb-Schultz-Mattis theorem is an example of such a constraint, but it is not known what the most general restriction might be. We focus on the existence of featureless paramagnets on the spin-1 square lattice and the spin-1 and spin-1/2 honeycomb lattice with spin rotation and space group symmetries in 2+1 dimensions.

Stimuli-responsive materials have attracted great interest in catalysis, sensing, and drug delivery applications and are typically constituted by soft components. We present a one-pot synthetic method for a type of inorganic silica-based shape change material that is responsive to water vapor exposure. After the wetting treatment, the cross-sectional shape of aminated mesoporous silica nanoparticles (MSNs) with hexagonal pore lattice changed from hexagonal to six-angle-star, accompanied by the loss of periodic mesostructural order.

We report measurements of the in-plane magnetoelastic coupling in both as-deposited and annealed ultrathin Ta/CoFeB/MgO layers as a function of uniaxial strain, conducted using a four-point bending apparatus. While as-deposited samples show only a weak dependence of the magnetoelastic coupling on the CoFeB layer thickness in the ultrathin regime (<2nm), we observe the onset of a strong thickness dependence upon annealing. This dependence can be modeled as arising from a combination of effective surface and volume contributions to the magnetoelastic coupling.

Helicases are a diverse group of molecular motors that utilize energy derived from the hydrolysis of nucleoside triphosphates (NTPs) to unwind and translocate along nucleic acids. These enzymes play critical roles in nearly all aspects of nucleic acid metabolism, and consequently, a detailed understanding of helicase mechanisms at the molecular level is essential.