U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Eric J. Cockayne (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 71

Graphing and Grafting Graphene: Classifying Finite Topological Defects

March 8, 2012
Author(s)
Eric J. Cockayne
The structure of finite-area topological defects in graphene is described in terms of both the direct honeycomb lattice and its dual triangular lattice. Such defects are equivalent to cutting out a patch of graphene and replacing it with a different patch

Rotational Grain Boundaries in Graphene

May 12, 2011
Author(s)
Eric J. Cockayne, Gregory M. Rutter, N Guisinger, Jason Crain, Joseph A. Stroscio, Phillip First
Defects in graphene are of interest for their effect on electronic transport in this two-dimensional material. Point defects of typically two-fold and three-fold symmetry have long been observed in scanning tunneling microscopy (STM) studies of graphite

Computational study of the dielectric properties of [La,Sc] 2 O 3 solid solutions

July 11, 2010
Author(s)
Hiroyoshi Momida, Eric J. Cockayne, Naoto Umezawa, Takahisa Ohno
First-principles calculations were used to compute the dielectric permittivities of hypothetical [La,Sc]2O3 solid solutions in the cubic (bixbyite) and hexagonal La2O3 phases. Dielectric enhancement is predicted at small Sc concentrations due to the

The Use of Apertures to Create Discrete Combinatorial Libraries Using Pulsed Laser Deposition

May 18, 2007
Author(s)
Nabil Bassim, Peter K. Schenck, Eugene Donev, Edwin J. Heilweil, Eric J. Cockayne, Martin L. Green, Leonard Feldman
In Pulsed-Laser Deposition (PLD), there are many processing parameters that influence film properties which may be studied such as substrate-target distance, background reactive gas pressure, laser energy, substrate temperature and composition in multi

Effects of Vacancies on Properties of Relaxor Ferroelectrics: A First-Principles Study

February 13, 2007
Author(s)
L Bellaiche, Jorge Iniguez, Eric J. Cockayne, Benjamin P. Burton
A first-principles-based model is developed to investigate the influence of lead vacancies on the properties of relaxor ferroelectric Pb(Sc1/2Nb1/2)O3 (PSN). Lead vacancies generate large, inhomogeneous, electric fields that reduce barriers between energy

Influence of Oxygen Vacancies on the Dielectric Properties of Hafnia

January 22, 2007
Author(s)
Eric J. Cockayne
First-principles calculations were used to study the effects of neutral and 2+ charged oxygen vacancies on the dielectric properties of crystalline HfO2. In agreement with previous results, the neutral vacancy is more stable on the 4-fold coordinated site

Local Structures and Raman Spectra in the Ca(Zr,Ti)O 3 Perovskite Solid Solutions

February 7, 2006
Author(s)
Igor Levin, Eric J. Cockayne, M W. Lufaso, Joseph C. Woicik, James E. Maslar
Local structures and cation distributions in perovskite Ca(Zr, Ti)O3 solid solutions were analyzed using X-ray absorption fine structure and pair-distribution functions obtained from total neutron scattering. The analyses revealed that the Zr-O and Ti-O

Wake Fields in the Electron Gas Including Transverse Response

January 19, 2006
Author(s)
Eric J. Cockayne, Zachary H. Levine
Relativistic electrons have transverse electric fields comparable in magnitude to the longitudinal fields. We determine the relative effects of transverse and longitudinal fields of a moving point charge on the dielectric response of a uniform electron gas

First Principles Based Simulations of Relaxor Ferroelectrics

January 16, 2006
Author(s)
Benjamin P. Burton, Eric J. Cockayne, Silvia Tinte, U Waghmare
The phenomenology of Pb(B,B$ {\prime}$)O$_{3}$, perovskite based relaxor ferroelectrics is reviewed, with emphasis on the relationship between chemical short-range order and the formation of polar nanoregions in the temperature range between the freezing

Generation of Lattice Wannier Functions via Maximum Localization

January 20, 2005
Author(s)
Eric J. Cockayne
A method is presented for generating approximate lattice Wannier functions (LWF) for lattice dynamics problems, using the dynamical matrix for a supercell as input. The lattice Wannier functions fit selected phonon frequencies and eigenvectors exactly, are

Lattice Dynamics in PbMg1/3Nb2/3O3

October 1, 2004
Author(s)
S A. Prosandeev, Eric J. Cockayne, Benjamin P. Burton, S Kamba, J Petzelt, Yu Yuzyuk, R S. Katiyar, S B. Vakhrushev

Dipole Moment of a Pb-O Vacancy Pair in PbTiO 3

April 1, 2004
Author(s)
Eric J. Cockayne, Benjamin P. Burton
The polarization of a nearest-neighbor (nn) Pb-O vacancy pair in PbTiO3 is calculated, using the modern theory of polarization, implemented in the density functional theory ultrasoft pseudopotential formalism. The dipole moment per divacancy is about 2.228