Materials Literature
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Nanoporous thin polymer films have been produced by a simple two-step approach using metallo-supramolecular block copolymers as the starting materials. The first step is the self-assembly of the copolymer, yielding cylindrical microdomains oriented normal to the substrate. The second step involves the opening of the m…
The mechanical oscillatory behavior of a C60 molecule tunneling through a carbon nanotube induced by van der Waals interaction are investigated by molecular-dynamics simulations. It is found that the C60 performs a decaying oscillation with a gradual decrease of the oscillatory amplitude and a gradual decrease of the…
Robust self-assembly with very high order is demonstrated by polyisobutylene-block-poly(ethylene oxide) (PIB–PEO) copolymers tailor-made by combining living cationic and anionic polymerization. A cubic micellar phase with long-range order and a glassy phase consisting of deformed spheroids are identified. Application…
Microcapsules with multilayer-thick shells are synthesized by depositing negatively charged nanoparticles around cationic polyamine aggregates crosslinked by multivalent counteranions (see Figure and inside cover). Unique among hollow-sphere preparative routes, this rapid and green synthesis leads to a robust organic/…
We present a systematic and realistic simulation for single and double phosphorous donors in a silicon-based quantum computer design. A two-valley equation is developed to describe the ground state of phosphorous donors in strained silicon quantum well (QW), with the central cell effect treated by a model impurity pot…
We discuss the dynamic impact ionization breakdown of high voltage p-n junction which occurs when the electric field is increased above the threshold of avalanche impact ionization on a time scale smaller than the inverse thermogeneration rate. The avalanche-to-streamer transition characterized by generation of dense…
Ab initio calculations for the giant magnetoresistance (GMR) in Co/Cu, Fe/Cr, and Fe/Au multilayers are presented. The electronic structure of the multilayers and the scattering potentials of point defects therein are calculated self-consistently. Residual resistivities are obtained by solving the quasi-classical Bolt…
The ground-state structures and ferroelectric properties of NbN (N=2-52) have been investigated by a combination of density-functional theory (DFT) in the generalized gradient approximation (GGA) and an unbiased global search with the guided simulated annealing. It is found that the electric dipole moment (EDM) exists…
Magnetic circular dichroism (MCD) of rutile Ti1−xCoxO2−δ is systematically examined with various x and δ to reveal a phase diagram for the appearance of ferromagnetism at higher carrier concentration and Co content. The phase diagram exactly matches with that determined from anomalous Hall effect (AHE). The magnetic f…
Bulk $\mathrm{Ni}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ is an insulating ferrimagnet. Here, we report on the epitaxial growth of spinel $\mathrm{Ni}{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$ ultrathin films onto $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$ single crystals. We will show that---under appropriate growth conditions---epi…
The RKKY interaction between substitutional Mn local moments in GaAs is both spin-direction dependent and spatially anisotropic. In this paper we address the strength of these anisotropies using a semiphenomenological tight-binding model that treats the hybridization between Mn $d$-orbitals and As $p$-orbitals perturb…
Several intramolecular junctions (IMJs) connecting two metallic (11, 8) and (9, 6) carbon nanotubes along their common axis have been realized by using a layer-divided technique to the nanotubes and introducing the topological defects. Atomic structure of each IMJ configuration is optimized with a combination of densi…
The first normal emission experiment result on bcc Ni ultrathin film is presented in comparison with the one on fcc Ni. Its agreement with band structure calculation, by supplementing our former results on the magnetic properties of bcc Ni, verifies from the electronic viewpoint the successful epitaxy of this metastab…
Quantum interference (QI) in two types of deformed carbon nanotubes (CNTs), i.e., axially stretched and AFM tip-deformed CNTs, has been investigated by the pi-electron only and four-orbital tight-binding (TB) method. It is found that the rapid conductance oscillation (RCO) period is very sensitive to the applied strai…
Carbon nanotube (CNT)-seeded controlled polymer crystallization provides a simple yet effective means to periodically modify CNT surfaces. Both single- and multiwalled CNTs have been successfully decorated with polyethylene and nylon-6,6 (see Figure and cover), implying that it might be a generic method for CNT functi…
Electrical conductivity of single-walled carbon nanotube (SWNT)–epoxy composites (see Figure) is investigated as a function of SWNT concentration, mean length, and aggregation. The composites exhibit a percolation-like conductivity with threshold volume fractions as low as 5.2 × 10–5. These low thresholds are attribut…
The rupture of rubber differs from conventional fracture. It is supersonic, and the speed is determined by strain levels ahead of the tip rather than total strain energy as for ordinary cracks. Dissipation plays a very important role in allowing the propagation of ruptures, and the back edges of ruptures must toughen…
Dicerium disilicate, Ce2[Si2O7], crystallizes in space group P41 of the tetragonal system. It has isostructural analogues among the disilicates of the larger rare-earth elements, namely Ln2[Si2O7] (Ln is La, Pr, Nd or Sm). The structure consists of discrete Ce3+ cations and [Si2O7]6− anions; the asymmetric unit conta…
The silver bismuth tridecasulfide Ag3.5Bi7.5S13 crystallizes in the monoclinic space group C2/m. Its structure is built up of two alternating kinds of layered modules parallel to (001). In the module denoted A, octahedra around the metal positions (M = Ag/Bi, M2 and an S atom on 2/m, other atoms on m) alternate with p…
Sodium-doped bismuth titanate undergoes a transformation from Bi4Ti3O12 to Na0.5Bi4.5Ti4O15 on heating in air at temperatures exceeding 800 °C. This transformation proceeds through the intermediate Na0.5Bi8.5Ti7O27 structure which is an intergrowth phase of the two. High-resolution transmission electron microscopy was…