Archive for December, 2011

Texture-Induced Modulations of Friction Force: The Fingerprint Effect

Thursday, December 8th, 2011

Modulations of the friction force in dry solid friction are usually attributed to macroscopic stick-slip instabilities.  Here we show that a distinct, quasistatic mechanism can also lead to nearly periodic force oscillations during sliding contact between an elastomer patterned with parallel grooves, and abraded glass slides.  The dominant oscillation frequency is set by the ratio [...]

Molecular Switch Based on Current-Driven Rotation of an Encapsulated Cluster within a Fullerene Cage

Monday, December 5th, 2011

By scanning tunneling microscopy imaging and electronic structure theory, we investigate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc3N cluster within an icosahedral C80 fullerene cage among three pairs of enantiomorphic configurations.  Bias-dependent action spectra and modeling implicate the antisymmetric stretch vibration of Sc3N cluster as the gateway for energy transfer [...]

Fully Printed Carbon Nanotube Thin Film Transistor Circuits

Monday, December 5th, 2011

The advantages of printed electronics and semiconducting single-walled carbon nanotubes (SWCNTs) are combined for the first time for display electronics.  Conductive silver ink and 98% semiconductive SWCNT solutions are used to print back-gated thin film transistors with high mobility, high on/off ratio, and high current carrying capacity.  In addition, with printed polyethylenimine with LiClO4 as [...]

Local Correlation Method for Metals

Friday, December 2nd, 2011

Highly accurate methods such as coupled cluster (CC) techniques can be used for periodic systems within the framework of the method of increments.  Its extension to low-dimensional conducting system is considered.  To demonstrate the presented approach a clean magnesium surface is selected, where the CC treatment with single and double excitations and perturbative triples is [...]

Theory of Strains in Auxetic Materials

Friday, December 2nd, 2011

Auxetic materials, or negative-Poisson’s-ratio materials, are important technologically and fascinating theoretically.  When loaded by external stresses, their internal strains are governed by correlated motion of internal structural degrees of freedom.  The modelling of such materials is mainly based on ordered structures, despite existence of auxetic behavior in disordered structures and the advantage in manufacturing disordered [...]