Materials Literature
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Highly crystallized TiO 2 nanocrystallites (10−50 nm in size) with controlled phase structures (anatase and rutile) were synthesized using a one-step process. Flying TiC micrometer-size powder was oxidized in Ar−O 2 and Ar−H 2 −CO 2 plasmas with various configurations used for injecting oxygen into the reaction system…
The effect of sidewall functionalization on the dielectrophoretic mobility of single-walled carbon nanotubes is investigated using a 10-μm electrode gap and an alternating current electric field of 10 V and 10 Mhz. For nanotubes dispersed in aqueous solution using 1% sodium dodecyl sulfate, a high degree of alignment…
The present work is concerned with a thermodynamics model that describes the redox switching of electroactive polymers. It is well-known that, during the redox switching of these polymers, the following phenomena occurs: (i) conformational changes, (ii) income/outcome of solvent molecules with the subsequent changes i…
Short-range ferroelectric order is postulated to explain unusual one-dimensional dielectric response in ferroelectric 1,4-diazabicyclo[2.2.2]octane. In this pure organic salt, the polar regions are created in the antiferroelectric matrix of hydrogen-bonded polycationic chains due to the random proton transfers in NH +…
The Mycobacterium tuberculosis genome contains an unusually high number of proteins involved in the metabolism of lipids belonging to the Lip family, including various nonlipolytic and lipolytic hydrolases. Driven by a structural genomic approach, we have biochemically characterized the Rv1399c gene product, LipH, pre…
We have investigated the in-plane switching of cholesteric liquid crystals for reflective wavelength shifters for visible and near-infrared applications. These devices are based on the elongation of the cholesteric pitch by an electric field perpendicular to the helical axis. The transmission notch-reflection peak pos…
High-quality short-wavelength-emitting Zn x Cd 1- x Se nanocrystals with emission wavelengths tunable from 440 to 550 nm have been prepared through the incorporation of a Zn precursor into the newly formed CdSe nuclei together with the remaining Cd/Se precursors (or Cd precursor into the ZnSe nuclei with the remaining…
By using first principles calculations, we show that fine tuning of both p- and n-type doping can be realized on single-wall carbon nanotubes (SWNTs) by tuning the electron affinity or ionization potential of the organic and organometallic molecules encapsulated inside SWNTs. This novel type of SWNT-based material off…
We have performed in situ x-ray and neutron-diffraction measurements, and molecular dynamics simulations, of GeO2, an archetypal network-forming glass under pressure. Below 5 GPa, additional atoms encroaching on the first tetrahedral shell are seen to be a precursor of local coordination change. Between 6 and 10 GPa,…
A quenchable superhard high-pressure carbon phase was synthesized by cold compression of carbon nanotubes. Carbon nanotubes were placed in a diamond anvil cell, and x-ray diffraction measurements were conducted to pressures of approximately 100 GPa. A hexagonal carbon phase was formed at approximately 75 GPa and prese…
The direct calculation of the elastic and piezoelectric tensors of solids can be accomplished by treating homogeneous strain within the framework of density-functional perturbation theory. By formulating the energy functional in reduced coordinates, we show that the strain perturbation enters only through metric tenso…
The electronic structure and magnetism in the sodium nickelate NaNiO_2 in the low-temperature phase is studied from density-functional calculations using the linear muffin-tin orbitals method. An antiferromagnetic solution with a magnetic moment of 0.7 m_B per Ni ion is found. A ferrodistorsive orbital ordering is sho…
We study the Aharonov-Bohm effect in the optical phenomena of single wall carbon nanotubes (SWCN) and also their chirality dependence. Specially, we consider the natural optical activity as a proper observable and derive it's general expression based on a comprehensive symmetry analysis, which reveals the interplay be…
Hole spin relaxation time due to the hole-acoustic phonon scattering in GaAs quantum dots confined in quantum wells along (001) and (111) directions is studied after the exact diagonalization of Luttinger Hamiltonian. Different effects such as strain, magnetic field, quantum dot diameter, quantum well width and the te…
We propose and numerically simulate novel reconfigurable logic gates employing spin metal-oxide-semiconductor field-effect transistors (spin MOSFETs). The output characteristics of the spin MOSFETs depend on the relative magnetization configuration of the ferromagnetic contacts for the source and drain, that is, high…
Si1-xGex/Si1-yGey/Si(100) heterostructures grown by Molecular Beam Epitaxy (MBE) were used in order to study B surface segregation during growth and B lattice diffusion. Ge concentration and stress effects were separated. Analysis of B segregation during growth shows that: i) for layers in epitaxy on (100)Si), B segre…
We observe field emission from an isolated nano-machined gold island. The island is able to mechanically oscillate between two facing electrodes, which provide recharging and detection of the emission current. We are able to trace and reproduce the transition from current flow through a rectangular tunneling barrier t…
Oxide superlattices and microstructures hold the promise for creating a new class of devices with unprecedented functionalities. Density-functional studies of the recently fabricated superlattices of lattice-matched perovskite titanates (SrTiO3)n/(LaTiO3)m reveal a classic wedge-shaped potential originating from the C…
We report the first experimental evidence of a magnetic phase arising due to the thermal blocking of antiferromagnetic clusters in the weakened charge and orbital ordered system ${\mathrm{P}\mathrm{r}}_{0.5}{\mathrm{C}\mathrm{a}}_{0.5}{\mathrm{M}\mathrm{n}}_{0.975}{\mathrm{A}\mathrm{l}}_{0.025}{\mathrm{O}}_{3}$. The t…
Self-assembly of robust perylenediimide chromophores is used to produce an artificial light-harvesting antenna structure that in turn induces self-assembly of a functional special pair that undergoes ultrafast, quantitative charge separation. The structure consists of four 1,7-(3',5'-di-tert-butylphenoxy)perylene-3,4:…