Mean free path

About: Mean free path is a research topic. Over the lifetime, 4412 publications have been published within this topic receiving 114418 citations.

Inelastic Electron Interactions in the Energy Range 50 eV to 10 keV in Insulators: Alkali Halides and Metal Oxides

Abstract: Calculations of electron inelastic mean free paths and stopping powers for several alkali halides (KF, KC1, KBr, and KI) and metal oxides (BeO, MgO, SiO 2 and Aj 2 O 3 ) have been performed in the 50 eV to 10 keV energy range The complex dielectric formalism, improved to include the energy gap, was used for estimating the valence part of the transport characteristics, whereas the part related to electron-core interactions was evaluated according to Gryzinski's theory An extended comparison of these calculations with the available experimental data as well as with other theoretical predictions is presented Trends of the energy dependence of the inelastic mean free path and stopping power in alkali halides are studied The role of the plasmon deexcitation process as a source for low-energy electrons in secondary electron emission spectra is discussed The presented data can be used in Monte-Carlo simulations of electron transport in the considered materials

Thickness dependence of the resistivity of Platinum group metal thin films

Abstract: We report on the thin film resistivity of several platinum-group metals (Ru, Pd, Ir, Pt). Platinum-group thin films show comparable or lower resistivities than Cu for film thicknesses below about 5\,nm due to a weaker thickness dependence of the resistivity. Based on experimentally determined mean linear distances between grain boundaries as well as ab initio calculations of the electron mean free path, the data for Ru, Ir, and Cu were modeled within the semiclassical Mayadas--Shatzkes model [Phys. Rev. B 1, 1382 (1970)] to assess the combined contributions of surface and grain boundary scattering to the resistivity. For Ru, the modeling results indicated that surface scattering was strongly dependent on the surrounding material with nearly specular scattering at interfaces with SiO2 or air but with diffuse scattering at interfaces with TaN. The dependence of the thin film resistivity on the mean free path is also discussed within the Mayadas--Shatzkes model in consideration of the experimental findings.

The mean free path of gas molecules in the transition régime

Abstract: Comparison is made between the electrical and thermal conductivities of solids and the transport properties of gases, with special reference to boundary limiting effects. The transition from continuum to molecular behaviour of gases is explored using a modified mean free path. Relative intermolecular and boundary collisions are calculated and it is proposed that, by assuming the transport process to be partially continuum and partially molecular, according to such frequencies, there results a plausible account for some of the observed `anomalies' in gas flow characteristics in the transition regime.

Size dependent thermal conductivity of single-walled carbon nanotubes

Abstract: In this paper, we report a non-equilibrium molecular dynamics study on the size-dependent thermal conductivity in single-walled carbon nanotubes with lengths up to micrometers at room temperature. It is found that the size-dependent thermal conductivity of single-walled carbon nanotubes can be described by κ(L,d)≈κg(L)(1−e−0.185d/a0), where L is the tube length, d is the diameter, a0=2.46 A is the graphene lattice constant, and κg(L)∝Lα is the thermal conductivity of a graphene of length L. In the above, α=1 for L l0, independent of the tube chirality (zigzag or armchair), where l0≈200 nm and 300 nm are the effective phonon mean free path for zigzag and armchair tubes, respectively. Physical interpretations of such geometry dependence are provided in the paper by analyzing the spectral energy density, the dispersion relationship, the phonon density of state, and the power spectrum of phonons.