Carbon nanotubes have interesting electromechanical properties that may enable a new class of nanoscale mechanical sensors. We fabricated two-terminal nanotube devices on silicon nitride membranes, measured their electronic transport versus strain, and estimated their band gaps and the strain-induced changes in them. We found band-gap increases and decreases among both semiconducting and small-gap semiconducting (SGS) tubes. The SGS band gaps exceeded the predicted curvature-induced gaps for their diameter. Some of the band-gap changes for both types of tubes exceeded the predicted maxima. These anomalies are likely caused by interaction with the rough silicon nitride surface.
Laser-cooled neutral atoms from a low-velocity atomic source are guided via a magnetic field generated between two parallel wires on a glass substrate. The atoms bend around three curves, each with a 15-cm radius of curvature, while traveling along a 10-cm-long track. A maximum flux of 2 · 10 6 atoms/sec is achieved with a current density of 3 · 10 4 A/cm 2 in the 100 × 100-µm-cross-section wires. The kinetic energy of the guided atoms in one transverse dimension is measured to be 42 µK. PACS numbers: 03.75.B, 32.80.P Just as optical waveguides play a central role in many aspects of modern optics, from communications to integrated optics, atom waveguides are likely to be an enabling technology for future atom-optics-based science. In particular, well-characterized atom waveguides may make possible inertial and rotation measurements of exquisite sensitivity via large-enclosed-area atom interferometers [1]. One of the first guides for atoms was based on optical forces, where hollow glass fibers guide light, and the light in turn guides atoms [2,3].Atom guiding using magnetic forces from current-carrying wires has been demonstrated more recently [4,5]. From the point-of-view of using atom-guides to pursue precision metrology goals [6] much benefit can be derived from patterning the waveguides on a rigid substrate. First, beamsplitters can be precisely and reproducibly fabricated.Second, the enclosed area of an interferometer can be precisely controlled. Third, the use of well-established lithographic techniques means that progress on individual optical elements (a beamsplitter, or a monochromator, for instance) can be rapidly extended to multi-component experiments. Mirrors based on micro-patterned wires have already been introduced [7]. We report magnetic guiding by a pair of parallel wires produced on a glass substrate by photolithography and subsequent electro-plating. Intricate two-dimensional guiding structures are easily produced by this manufacturing technique; in the present case, it allows us to demonstrate guiding around curves in a 10 cm long
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.