Materials Literature
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We investigate numerically various properties of the one-dimensional (1D) breathing-mode polaron. We use an extension of a variational scheme to compute the energies and wave-functions of the two lowest-energy eigenstates for any momentum, as well as a scheme to compute directly the polaron Greens function. We contras…
Abstract We report a facile approach for the spontaneous formation of silver nanoparticles in the presence of gum acacia polymer (a natural polymer) without the addition of any typical reducing agent under mild conditions. Silver nanoparticles (∼ 5 nm) have been obtained by the mixing of equal amounts of 0.5 wt % aque…
Due to the competition between spatial and magnetic confinement, the density of states of a quasi two-dimensional system deviates from the ideal step-like form both quantitatively and qualitatively. We study how this affects the spin-subband populations and the spin-polarization as functions of the temperature, $T$, a…
We report measurements of the thermal expansion for two Eu$^{+2}$- and two Gd$^{+3}$-based intermetallics which exhibit ferro- or antiferromagnetic phase transitions. These materials show sharp positive (EuAgMg and GdAuMg) and negative (EuAuMg and GdAgMg) peaks in the temperature dependence of the thermal expansion co…
Violet Lander (VL) (C108H104) is a large organic molecule that when deposited on Cu (110) exhibited lock-and-key like behavior (Otero et al., Nature Mater. 3, 779 (2004)). In this work we report on a detailed fully atomistic molecular dynamics study of this phenomenon. Our results show that it has its physical basis i…
Phase field models have been applied in recent years to grain boundaries in single-component systems. The models are based on the minimization of a free energy functional, which is constructed phenomenologically rather than being derived from first principles. In single-component systems the free energy is a functiona…
We present a theoretical analysis of recent experimental measurements of magnetoresistance in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ epilayers with perpendicular magnetic anisotropy. The model reproduces the field-antisymmetric anomalies observed in the longitudinal magnetoresistance in the pla…
Abstract We present a detailed study of a new, optimized coarse‐grained (CG) model of polystyrene (PS) and compare it with a recently published one (Harmandaris et al., Macromolecules 2006 , 39 , 6708). By implementing a different mapping scheme, the new model, augmented with softer nonbonded interactions, better repr…
Standard density functional approximations greatly over-estimate the static polarizability of longchain polymers, but Hartree-Fock or exact exchange calculations do not. Simple self-interaction corrected (SIC) approximations can be even better than exact exchange, while their computational cost can scale only linearly…
We study the electron transport properties through a supported organic molecule styrene (C8H8) on an ideal silicon surface Si[111] and probed by a STM-tip. The I-V characteristics and the differential conductance of the molecule are calculated using a self consistent approach based on non equilibrium Green's functions…
Salt-induced aggregation of 20 nm colloidal silica is followed by light transmission, which shows an a kinetic form exp[-(t/t_0)^α], where α= 2.6 and t_0 is an empirical time constant which reflects the colloidal stability. We found a power law dependence of t_0 on ionic strength, which can be explained by the classic…
We report formation of self organized InP nano dots using 3 keV Ar+ ion sputtering, at $15^\circ$ incidence from surface normal, on InP(111) surface. Morphology and optical properties of the sputtered surface, as a function of sputtering time, have been investigated by Scanning Probe Microscopy and Raman Scattering te…
To better understand the electronic and chemical properties of wide-gap oxide surfaces at the atomic scale, experimental work has focused on epitaxial films on metal substrates. Recent findings show that these films are considerably thinner than previously thought. This raises doubts about the transferability of the r…
A thermally reversible culture substrate with a topographically active surface of aligned nanofibers is able to induce cytoskeletal alignment and nucleus elongation. These morphological changes induce myogenic differentiation in stem cells. The differentiated cells can be recovered in sheet form by thermally induced d…
Electromagnetic invisibility cloak requires material with anisotropic distribution of the constitutive parameters as first proposed by Pendry et al. [Science 312, 1780 (2006)]. In this paper, we proposed an electromagnetic cloak structure that does not require metamaterials with subwavelength structured inclusions to…
Control over ferroelectric polarization variants in BiFeO3 films through the use of various vicinal SrTiO3 substrates is demonstrated. The revolution of domain formation as a function of vicinality is characterized, and the ferroelectric polarization variants in these films and the corresponding structural variants ar…
Abstract A simple synthesis route to mesoporous carbons that contain heteroaromatic functionality is described. The sulfur‐functionalized mesoporous carbon (S‐FMC) materials that have been prepared show excellent thermal stability, as well as excellent hydrothermal stability, and stability over a wide range of pH valu…
In this paper, the upconversion luminescent properties of Y 2 O 3:Er 3+ (1%)/Yb 3+ (4%) nanoparticles with different sizes (13−55 nm) and its corresponding bulk material as a function of excitation power were studied under 978-nm excitation. Red ( 4 F 9/2 → 4 I 15/2 ), green ( 2 H 11/2, 4 S 3/2 → 4 I 15/2 ), and blue…
This study revealed the nature of native defects and their roles in ZnO through positron annihilation and optical transmission measurements. It showed oxygen vacancies are the origin for the shift in the optical absorption band that causes the red or orange coloration. It also revealed experimental evidence that the d…
Methotrexate (MTX), a stoichiometric inhibitor of dihydrofolate reductase, is a chemotherapeutic agent for treating a variety of neoplasms. Impairment of drug import into cells and increase in drug export from cells may render cells resistant to MTX. MTX, when locally administered in a soluble form, is rapidly absorbe…