Temperature dependent He-enhanced damage and strain in He-implanted AlN

Micro-Raman spectroscopic visualization of lattice vibrations and strain in He- implanted single-crystal LiNbO3

Scanning micro-Raman spectroscopy has been utilized to image and investigate strain in He-implanted congruent LiNbO3 samples. By using abruptly patterned implanted samples, we show that the spatial twodimensional mapping of the Raman spectral peaks can be used to image the strain distribution and determine its absolute magnitude. We demonstrate that both shortand long-range length-scale in-plan...

Autoionization of He and Autodetachment of He- following Bombardment by H+, H2+, He+, and He Atoms

Calculations of the binding energies of weakly bound He–He–H, He–He–H− and He–H–H molecules

We searched for the existence of weakly bound He–He–H, He–He–H− and He–H– H molecules where the binding energies are expected to be of the order of degrees Kelvin. By employing the best empirical interaction between each pair of particles, we solved the Schrödinger equation for the triatomic systems using hyperspherical coordinates in the adiabatic approximation. We found no bound states for 4H...

Low Temperature Transport Properties of Very Dilute Classical Solutions of 3 He in Superfluid 4 He

We report microscopic calculations of the thermal conductivity, diffusion constant and thermal diffusion constant for classical solutions of He in superfluid He at temperatures T < ∼0.6 K, where phonons are the dominant excitations of the He. We focus on solutions with He concentrations < ∼ 10, for which the main scattering mechanisms are phonon-phonon scattering via 3-phonon Landau and Beliaev...

One-dimensional Excitations in Superfluid He and He-He Mixture Films Adsorbed in Porous Materials

(Dated: February 1, 2008) A normal-fluid component varying as T is observed at very low temperatures in superfluid He and He-He mixture films adsorbed in alumina powder. The normal fluid appears to arise from thermally excited third sound that has one-dimensional propagation characteristics. A Landau model of third sound excitations in an infinite cylindrical pore by Saam and Cole provides good...