Materials Literature
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The persistent proximity of insulating and metallic phases, a puzzling characteristic of manganites, is argued to arise from the self-organization of the twofold degenerate e(g) orbitals of Mn into localized Jahn-Teller (JT) polaronic levels and broad band states due to the large electron-JT phonon coupling present in…
Exquisite nanoscale architectures are exhibited by siliceous diatom shells (see picture of the cell wall of Stephanopyxis turris). A hierarchy of hexagonal silica structures is a major motif. Long-chain polyamines are a constituent of biosilica and had been proposed to be involved in pattern formation. In vitro studie…
Dressed up to the nines: A nonanuclear FeII complex exhibiting rare μ4:η1 azido bridges that induce ferromagnetic exchange interactions possesses a core with a very large ground-state spin (probably S=14, see picture). The combination of a large S value and the magnetic anisotropy of iron(II) centers endows this uniqu…
In alloys cluster expansions (CE) are increasingly used to combine first-principles electronic-structure and Monte Carlo methods to predict thermodynamic properties. As a basis-set expansion in terms of lattice geometrical clusters and effective cluster interactions, the CE is exact if infinite, but is tractable only…
Using angle resolved photoemission we have investigated annealing-induced changes in Ga(1-x)Mn(x)As with x = 0.05. We find that the position of the Fermi energy is a function of annealing time and temperature. It is also established that the Curie temperature is strongly correlated to the separation between the Fermi…
We report on the nonlinear optical dynamical properties of excitonic complexes in CdTe modulation-doped quantum wells, due to many-body interactions among excitons, trions and electrons. These were studied by time and spectrally resolved pump-probe experiments. The results reveal that the nonlinearities induced by tri…
We report extensive first-principles calculations of the inelastic lifetime of low-energy electrons in the noble metals Cu, Ag, and Au. The quasiparticle self-energy is computed with full inclusion of exchange and correlation (xc) effects, in the framework of the GWΓapproximation of many-body theory. Although exchange…
We show that some metals and alloys (X = Cu, Ag, FeMn, or Cu and Ag combined with each other), sputtered between ferromagnetic Co and superconducting Nb, produce no change in current-perpendicular-to-plane magnetoresistance (CPP-MR) in a carefully designed CPP-spin-valve. In contrast, other metals (Ru or Au) or combin…
Charge migration along DNA molecules has attracted scientific interest for over half a century. Reports on possible high rates of charge transfer between donor and acceptor through the DNA, obtained in the last decade from solution chemistry experiments on large numbers of molecules, triggered a series of direct elect…
The frequency dependent ac conductivity and permittivity of porous lead zirconate titanate ceramic with the pore volume filled with water are shown to match the simulated electrical response of a large network of randomly positioned resistors and capacitors. Anomalous power law dispersions in conductivity and permitti…
In the last years there has been a great interest in magnetic systems formed by a cluster of transition metal ions covalently bonded via superexchange bridges, embedded in a large organic molecule. Following the synthesis and the structural and magnetic characterization of these magnetic molecules by chemists, the phy…
In the last years there has been a great interest in magnetic systems formed by a cluster of transition metal ions covalently bonded via superexchange bridges, embedded in a large organic molecule. Following the synthesis and the structural and magnetic characterization of these magnetic molecules by chemists, the phy…
The aqueous synthesis and post-preparative treatment of thiol-stabilized ZnSe colloidal nanocrystals (2−3 nm in size) have been studied. The post-preparative irradiation of the nanoparticles improves their luminescence properties leading to strong (up to 25−30% photoluminescence quantum yield) band gap UV-blue emissio…
Perovskite nanoparticles were obtained by treating alkali or alkaline-earth metals dissolved in benzyl alcohol with transition metal alkoxides, which is a novel and generally applicable route to nanosized perovskites and related materials. In the picture, the synthetic route to BaTiO3 nanocrystals is superimposed on a…
Ferroelectric BiFeO 3 thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate by pulsed-laser deposition. From the X-ray diffraction analysis, the BiFeO 3 thin film consists of perovskite single-phase, and the crystal structure shows the tetragonal structure ( c / a = 1.018) with a space group P 4 m m . It is…
Au/Ag core/shell nanorods with different shell thickness were synthesized in aqueous solution by chemically depositing silver on gold nanorods surface. With the silver coating, the longitudinal plasmon mode of the nanorods shifted blue and was enhanced. A dipole-limit calculation, based on confocal ellipsoids, simulat…
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The energy distribution of electrons quasi-elastically backscattered from solids has been investigated. Monte Carlo (MC) simulations were performed for the study of the recoil energy shift and the broadening of this distribution for backscattered electrons from Si and Au. In these simulations, electron interaction cro…
We have observed 90° domain walls in a bulk BaTiO 3 crystal by synchrotron radiation topography, coupled with a CCD detector. The BaTiO 3 multi-domain crystal was revealed to be strained at the 90° domain boundary. The polar direction of the BaTiO 3 crystal was tilted by this strain, and this strain also causes the ir…
We performed the X-ray diffraction measurements at low temperature under ambient pressure for the pressure-induced superconductor β'-Cu 0.65 V 2 O 5 . Satellite reflections were observed with an incommensurate modulation and a successive commensurate state depending on the cooling rate. The X-ray structure analysis in…