Materials Literature
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We compare electrical and mechanical properties of C70 fullerene with high purity graphite to 48 GPa at room temperature using designer diamond anvils with embedded electrical microprobes. The electrical resistance of C70 shows a minimum at 20 GPa with transformation to an amorphous insulating phase complete above 35…
Critical behavior of the metal-insulator transition (MIT) coupled with spin/orbital correlations has been investigated for single crystals of La1-(x)Sr(x)VO3. In the paramagnetic (PM) metal phase (x > 0.260), the precursor to the MIT manifests itself as an enhancement of carrier effective mass. In the antiferromagneti…
Molecular dynamics simulations are used to generate an ensemble of saddles of the potential energy of a Lennard-Jones liquid. Classifying all extrema by their potential energy u and number of unstable directions k, a well-defined relation k(u) is revealed. The degree of instability of typical stationary points vanishe…
We numerically investigate the supercooled dynamics of two simple model liquids exploiting the partition of the multidimensional configuration space in basins of attraction of the stationary points (inherent saddles) of the potential energy surface. We find that the inherent saddle order and potential energy are well-…
We have calculated the crystal electric field of TmTe (T>T_Q) and have obtained that the ground state of a Tm 4f hole is the $Γ_7$ doublet in agreement with Mossbauer experiments. We study the quadrupole interactions arising from quantum transitions of 4f holes of Tm. An effective attraction is found at the L point of…
We present a new algorithm for quantum Monte Carlo simulation based on global updating with loops. While various theoretical predictions are confirmed in one dimension, we find, for S=1 systems on a square lattice with an antiferromagnetic biquadratic interaction, that the intermediate phase between the antiferromagne…
We conduct extensive molecular dynamics computer simulations of two models for liquid silica [the model of Woodcock, Angell and Cheeseman, J. Phys. Chem. 65, 1565 (1976); and that of van Beest, Kramer, and van Santen, Phys. Rev. Lett. 64, 1955 (1990)] to determine their thermodynamic properties at low temperature T ac…
The phase diagram of the organic superconductor kappa-(ET)2Cu[N(CN)2]Cl has been accurately measured from 1H NMR and ac susceptibility techniques under helium gas pressure. The domains of stability of antiferromagnetic and superconducting orders in the pressure vs temperature plane have been determined. Both phases ov…
We review and compare electronic transport in different types of conducting polymer: conjugated organic polymers, the inorganic polymer polysulphur nitride, alkali-metal fulleride polymers, and carbon nanotubes. In each case, the transport properties show some unusual features compared to conventional metals. In conju…
Polarized micro-Raman spectroscopy has been performed on spatially separated single-wall carbon nanotubes (SWNTs) in the form of individual nanotubes or thin ropes of only a few SWNTs. Different from bulk samples, the Raman spectra are composed of well-resolved peaks which allow a direct comparison of experimental dat…
Electron microscope imaging for gadolinium metallofullerenes encapsulating in single-wall carbon nanotubes $[(\mathrm{Gd}@\mathrm{C}{}_{82}{)}_{n}@\mathrm{SWNTs}]$ identifies the single Gd atom encaged in each. The intermolecular distance between $\mathrm{Gd}@\mathrm{C}{}_{82}$ is extremely regular, regarding the chai…
Thin films of β-Ga2O3 with an energy band gap of 4.9 eV were prepared on silica glass substrates by a pulsed-laser deposition method. N-type conductivity up to ∼1 S cm−1 was obtained by Sn-ion doping and deposition under low O2 partial pressure (∼10−5 Pa) at substrate temperatures above 800 °C. The resulting internal…
Reactions of M(allyl) 3 [M = Rh, Ir] with a variety of donor ligands have been investigated. While both complexes are unreactive toward “hard” N- and O-donor ligands, “soft” ligands such as tolylisothiocyanate, tertiary phosphines, CO, and aryl isocyanides are readily added. Whereas ligand additions to Rh(allyl) 3 are…
Cp2M(dithiolene) (M = MoIV, WIV) d2 complexes exhibit a folding (theta) of the MS2C2 metallacycle along the S-S axis upon oxidation to the d1 paramagnetic cation. The evolution of the peculiar unfolded structure (theta = 0 degree) of Cp2Mo(dmit).+ (dmit2-, 2-thioxo-1,3-dithiole-4,5-dithiolate) in its AsF6- salt toward…
A new addition to the family of single-molecule magnets is reported: an Fe10 cage stabilized with benzoate and pyridonate ligands. Monte Carlo methods have been used to derive exchange parameters within the cage, and hence model susceptibility behavior.
Molecular dynamics computer simulations of Mg/Al hydrotalcite with interlayer Cl - were performed to better understand the structure of layered double hydroxides and their hydration behavior. A set of models with variable numbers of interlayer water molecules was investigated, with the assumption of no constraints on…
A synthesis procedure is described for making functionalized mesoporous silica macrostructures that can serve as self-supporting adsorbents for environmental remediation and other separations applications. The material, whose mesopores were functionalized with 3-mercaptopropyltrimethoxysilane ligands, can be made into…
Monodisperse polyphenylene dendrimers up to the fourth generation were synthesized using a divergent growth protocol. By varying the core, dendrimers with dumbbell-, tetrahedral- and propeller-like structures were synthesized. Because of the high-density packing of benzene rings within their branches, these dendrimers…
The electrical and magnetic properties of kappa-(BETS)(2)FeBr(4) salt [where BETS = bis(ethylenedithio)tetraselenafulvalene] showed that this system is the first antiferromagnetic organic metal at ambient pressure (T(N) = 2.5 K). The characteristic field dependence of the magnetization at 2.0 K indicates a clear metam…
As a model system for the photoinduced/photoswitched spin alignment in a purely organic pi-conjugated spin system, 9-[4-(4,4,5,5-tetramethyl-1-yloxyimidazolin-2-yl)phenyl]anthracene (1a), 9-[3-(4,4,5,5-tetramethyl-1-yloxyimidazolin-2-yl)phenyl]anthracene (1b), 9,10-bis[4-(4,4,5,5-tetramethyl-1-yloxyimidazolin-2-yl)phe…