arXiv subjects

Jack J. Shi

Publications and source records attributed to Jack J. Shi.

3 recordsLinked to original sources

arXiv2017

A general formalism of two-dimensional lattice potential on beam transverse plane for studying channeling radiation

To study channeling radiation produced by an ultra-relativistic electron beam channeling through a single crystal, a lattice potential of the crystal is required for solving the transverse motion of beam electrons under the influence of the crystal lattice. In this paper, we present a general formalism for this two-dimensional lattice potential of a crystal with a Lorentz contraction in the beam channeling direction. With this formalism, the lattice potential can be calculated without approximation from any given model of electron-ion interaction for an ultra-relativistic beam channeling in any crystal direction. The formalism presented should be the standard recipe of the lattice potential for studying the channeling radiation.

cond-mat.other↗

arXiv2011

Transition of Impurity Nanorod Orientation in Epitaxial YBCO Films on Vicinal Substrates

A theoretical study of the structural transition of impurity nanorod array in epitaxial YBCO films on vicinal STO substrates is presented. Two possible types of film/substrate interface were considered with one assuming a complete coherence while the other, defective as manifested in presence of anti-phase grain boundaries. Only in the former case, the increase of the vicinal angle of the substrate leads to a substantial change of the strain field in the film, resulting in a transition of the nanorod orientation from the normal to in-plane direction of the film. The calculation of the threshold vicinal angle for the onset of the transition and the lattice deformation of the film due to the inclusion of the impurity nanorods is in very good agreement with experimental observations.

cond-mat.mtrl-sci↗

arXiv2011

Micromechanical Model for Self-Organized Impurity Nanorod Arrays in Epitaxial YBCO Films

A micromechanical model based on the theory of elasticity has been developed to study the configuration of self-assembled impurity nanostructures in high temperature superconducting YBCO films. With the calculated equilibrium strain and elastic energy of the impurity doped film, a phase diagram of lattice mismatches $vs.$ elastic constants of the dopant was obtained for the energetically-preferred orientation of impurity nanorods. The calculation of the nanorod orientation and the film lattice deformation has yielded an excellent agreement with experimental measurements.

cond-mat.mtrl-sci↗