The quantum transport properties of a Cu-CNT composite are studied using a non-equilibrium Green's function approach combined with the self-consistent-charge density-functional tight-binding method. The results show that the electrical conductance of the composite depends strongly on CNT density and alignment but more weakly on chirality. Alignment with the applied bias is preferred and the con...

SnO2 is widely used as a transparent conductor and sensor material. Better understanding and control of its conductivity would enhance its performance in existing applications and enable new ones, such as in light emitters. Using density functional theory, we show that the conventional attribution of n-type conductivity to intrinsic point defects is incorrect. Unintentional incorporation of hyd...

We report on the transient photoconductivity of hot carriers in undoped bulklike In0.53Ga0.47As observed via time-resolved terahertz far-infrared spectroscopy. For very dilute photoexcitation densities of ,1310 cm and an initial excess carrier energy of 630 meV, we find that electrons have an effective intervalley L→G return time of 3.1 ps as measured via the increased electrical conductivity a...

We report on ultrafast optical experiments in which femtosecond midinfrared radiation is used to excite the lattice of complex oxide heterostructures. By tuning the excitation energy to a vibrational mode of the substrate, a long-lived five-order-of-magnitude increase of the electrical conductivity of NdNiO(3) epitaxial thin films is observed as a structural distortion propagates across the int...

Lipid peroxidation (LPO) of unsaturated fatty acids in bimolecular lipid membranes (BLM), induced by ultraviolet irradiation [l-3] or by chemical agents [4], brings about an increase in conductivity of these membranes. For BLM prepared from egg phosphatidylcholine/cholesterol mixture this effect is accounted for by the rise of proton permeability [3,5]; the maximal conductivity enhancement bein...

The microstructure of a porous medium and physical characteristics of the solid and the fluids that occupy the pore space determine the macroscopic transport properties of the medium. The computation of macroscopic properties from the rock microtomography is becoming an increasingly studied topic. The transport properties are especially difficult to determine at the microscopic scale. In this p...

When a seismic wave propagates in a uid-saturated porous medium, a seismoelectric eld can be induced in the medium due to an electric double layer at the interface between solid and uid. The strength of the seismoelectric eld depends on the characteristics of the double layer and the conductivity of the saturant uid. In our experiments two kinds of seismoelectric elds, a radiating electromagnet...

Monte Carlo simulations and tight-binding calculations shed light on the properties of three-dimensional nanographene, a material composed of interlinked, covalently-bonded nanoplatelet graphene units. By constructing realistic model networks of nanographene, we study its structure, mechanical stability, and optoelectronic properties. We find that the material is nanoporous with high specific s...

We report the first experimental evidence for a metallic phase in fluid molecular oxygen. Our electrical conductivity measurements of fluid oxygen under dynamic quasi-isentropic compression show that a nonmetal-metal transition occurs at 3.4 fold compression, 4500 K, and 1.2 Mbar. We discuss the main features of the electrical conductivity dependence on density and temperature and give an inter...

The electrical conductance of epitaxial Bi thin films grown on BaF(2)(111) by molecular beam epitaxy has been systematically investigated as a function of both film thickness (4-540 nm) and temperature (5-300 K). Unlike bulk Bi as a prototypical semimetal, the Bi thin films up to 90 nm are found to be insulating in the interior but metallic on the surface. This finding not only has unambiguousl...