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Full-Text Articles in Physics
First-Principles Calculations Of Piezoelectricity And Polarization Rotation In Lead Zirconate Titanate, Zhigang Wu
First-Principles Calculations Of Piezoelectricity And Polarization Rotation In Lead Zirconate Titanate, Zhigang Wu
Dissertations, Theses, and Masters Projects
Recent experimental and theoretical work indicates that polarization rotation via a monoclinic phase at the morphotropic phase boundary in PZT is responsible for its large piezoelectric response. We performed Linearized augmented plane wave with the local orbital extension (LAPW+LO) method within local density approximation (LDA) on B-site [001]1:1 ordered Pb(Zr 0.5Ti0.5)O3 (PZT 50/50). We use a tetragonal super-cell and constrain it with monoclinic Cm space group. Atomic forces following the formulation of Yu et al. are calculated, and the conjugate gradient method is implemented to optimize the internal coordinates. Both the tetragonal (P4mm) and monoclinic (Cm) phases are reproduced, when …
Effects Of Longitudinal Disorder On The Magnetic Field Distribution In Bismuth Strontium Calcium Copper Oxide, Xuewen Wan
Dissertations, Theses, and Masters Projects
Transverse Field muon spin relaxation (TF-muSR) experiments were performed in external magnetic fields 1.0, 2.7, 3.0, 4.5, 5.5, 6.0 and 7.0 T along the Bi2212 crystalline c-axis. For the first time, the heterodyned fitting analysis technique shows that the field profiles on the ab basal planes of single crystal Bi2212 are symmetric in all experimental fields 1.0--7.0 T and at all experimental temperatures 2.0-90.0 K. The muon spin relaxation rates due to the mixed state of Bi2212 were found to increase linearly from 0 mus-1 at the transition temperature, 90.0 K, to about 1.0 mus -1 at the lowest temperature, …
The Ground State Of Two-Dimensional Hubbard-Like Models, Eric Christopher Allman
The Ground State Of Two-Dimensional Hubbard-Like Models, Eric Christopher Allman
Dissertations, Theses, and Masters Projects
We present results from a constrained path Monte Carlo (CPMC) study of a modified two-dimensional Hubbard model. We include more general forms of the band structure and electron interaction in order to examine their effects on ground-state properties, such as electron pairing correlations. Both next-nearest neighbor hopping, t', and third-nearest neighbor hopping, t″, are introduced in the Hamiltonian. A nearest neighbor interaction of strength V is also included. We carry out CPMC calculations on system sizes up to 16 x 16, at various electron fillings, to investigate the ground state of the model for different values of these parameters. For …
The Ortho To Para Transition In Muonic Molecular Hydrogen, Jessica Higgins Deseret Clark
The Ortho To Para Transition In Muonic Molecular Hydrogen, Jessica Higgins Deseret Clark
Dissertations, Theses, and Masters Projects
A precise measurement of the induced weak pseudoscalar coupling constant of the proton, gp, is of interest as a basic test of chiral symmetry breaking. This is the least well-known weak form factor of the nucleon. Muon capture experiments [Jonkmans et al., Phys. Rev. Lett. 77(1996)4512] have been used to measure gp. However, the interpretation of these muon capture experiments requires knowledge of the relative population of the muonic atomic and molecular states for muons in liquid hydrogen. In particular, lambda op, the transition rate between the ortho- and para-molecular states of the pmup molecule, needs to be known with …