Browsing Physics (Scholarly Publications) by Author "PATTERSON, CHARLES"
Now showing items 1-20 of 21
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Band structures of rare gas solids within the GW approximation
PATTERSON, CHARLES (2005)Band structures for solid rare gases s Ne, Ar d have been calculated using the GW approximation. All electron and pseudopotential ab initio calculations were performed using Gaussian orbital basis sets and the ... -
Defect-trapped electrons and ferromagnetic exchange in ZnO
CHAKRABARTY, AURAB; PATTERSON, CHARLES (2011)A model for ferromagnetism observed at ambient temperature in films of oxides such as ZnO is proposed and evaluated. The ferromagnetic moment in the model arises from electrons trapped at negatively charged vacancies in ... -
Dielectric anisotropy of the GaP/Si(001) interface from first-principles theory
PATTERSON, CHARLES (2017) -
Electronic Structure and Lattice Vibrations of Ca2CuO2Cl2: a hybrid density functional study
PATTERSON, CHARLES (2008)The electronic structure and phonon modes of Ca 2 CuO 2 Cl 2 have been calculated using hybrid density functional theory HDFT methods. The material is correctly predicted to be an antiferromagnetic insulator with ... -
Exchange coupling in CaMnO3 and LaMnO3: Configuration interaction and the coupling mechanism
PATTERSON, CHARLES (2002)The equilibrium structure and exchange constants of CaMnO3 and LaMnO3 have been investigated using total-energy unrestricted Hartree-Fock (UHF) and localized orbital configuration interaction (CI) calculations on bulk ... -
Ferromagnetic polarons in La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3
PATTERSON, CHARLES (2003)Unrestricted Hartree-Fock calculations on La0.5Ca0.5MnO3 and La0.33Ca0.67MnO3 in the full magnetic unit cell show that the magnetic ground states of these compounds consist of 'ferromagnetic molecules' or polarons ordered ... -
First Principles Calculation of the Structure and Dielectric Properties of Bi2Ti2O7
PATTERSON, CHARLES (2010)The structure, vibrational modes, and phonon contribution to the dielectric function of the pyrochlore Bi 2 Ti 2 O 6 O were calculated using first-principles methods. Total-energy minimization calculations were ... -
Group V adsorbate structure on vicinal Ge(001) surfaces determined from the optical spectrum
PATTERSON, CHARLES; MCGILP, JOHN (2017) -
High resolution electron energy loss spectroscopy of clean and hydrogen covered Si(001) surfaces: First principles calculations
PATTERSON, CHARLES (2012)Surface phonons, conductivities, and loss functions are calculated for reconstructed (2×1), p(2×2) and c(4×2) clean Si(001) surfaces, and (2×1) H and D covered Si(001) surfaces. Surface conductivities perpendicular to the ... -
Hybrid density functional theory applied to magnetite: Crystal structure, charge order, and phonons
PATTERSON, CHARLES (2009)The electronic structure and equilibrium structure of magnetite (Fe3O4) in the high temperature cubic Fd3¯m and low temperature monoclinic P2/c unit cells have been computed using the Perdew-Wang generalized gradient ... -
Hybrid DFT calculation of 57Fe NMR resonances and orbital order in magnetite
PATTERSON, CHARLES (2014)The crystal structure and charge and orbital order of magnetite below the Verwey temperature are calculated using a first-principles hybrid density functional theory (DFT) method. The initial atomic positions in ... -
Optical and phonon excitations of modified Pandey chains at the Si(111)-2×1 surface
PATTERSON, CHARLES; MCGILP, JOHN (2011)The modified Pandey π-bonded chain structure for the (2×1) reconstruction of the Si(111) surface has two nearly degenerate structures in which one or the other of two atoms in the π chain is the outermost atom at the ... -
Raman study of phonon modes in bismuth pyrochlores
PATTERSON, CHARLES (2010)The Raman spectra of the cubic bismuth pyrochlores Bi3/2Zn0.92Nb3/2O6.92, Bi3/2ZnTa3/2O7, Bi3/2MgNb3/2O7, and Bi3/2MgTa3/2O7 have been measured at room temperature. The frequencies of the Raman modes, obtained from ... -
Reflectance anisotropy spectroscopy of Si(111)-(3 x 1)Li and Ag surfaces
MCGILP, JOHN; PATTERSON, CHARLES (2013)The Si(111)-(3 × 1)Li and Ag surface structures consist of Si honeycomb chains separated by channels occupied by Li or Ag atoms. The dimerization of neighboring Ag atoms results in a larger c (12 × 2)Ag superstructure. ... -
Reflectance anisotropy spectroscopy of Si(111)-(3×1)Li and Ag surfaces
PATTERSON, CHARLES; MCGILP, JOHN (2013)The Si(111)-(3?1)Li and Ag surface structures consist of Si honeycomb chains separated by channels occupied by Li or Ag atoms. The dimerization of neighboring Ag atoms results in a larger c(12?2)Ag superstructure. We report ... -
Role of defects in ferromagnetism in Zn1-xCoxO: A hybrid density functional study
PATTERSON, CHARLES (2006)Experimental studies of Zn1−xCoxO as thin films or nanocrystals have found ferromagnetism and Curie temperatures above room temperature and that p- or n-type doping of Zn1−xCoxO can change its magnetic state. Bulk Zn1−xCoxO ... -
A simulation study of the kinetics of passage of CO2 and N2 through the liquid/vapor interface of water
PATTERSON, CHARLES (1999)The rate of passage of molecules of carbon dioxide and nitrogen through the vapor–liquid interface of water at 300 K is studied by simulation. Previous work has established the form of the free energy profile which has ... -
Small polarons and magnetic anti-phase boundaries in Ca2−xNaxCuO2Cl2 (x=0.06,0.12): origin of striped phases in cuprates
PATTERSON, CHARLES (2008)We report hybrid density functional theory calculations on hole doped Ca2−xNaxCuO2Cl2 performed in 4×4, 4√2×4√2, and 8×2 supercells with hole concentrations x=0.0625 and x=0.125. Holes at the lower concentration form small ... -
Soft x-ray spectroscopic investigation of ferromagnetic Co-doped ZnO
MCGUINNESS, CORMAC; LUNNEY, JAMES; PATTERSON, CHARLES; VENKATESAN, MUNUSWAMY; COEY, JOHN (2006)The electronic properties of cobalt-doped ZnO were investigated through site-selective and element-sensitive x-ray-absorption spectroscopy in the vicinity of the Co L2,3 edge, the oxygen K edge, and at the Zn L3 edge. ... -
Spin polaron effective magnetic model for La0.5Ca0.5MnO3
PATTERSON, CHARLES (2004)The conventional paradigm of charge order for La1−xCaxMnO3 for x=0.5 has been challenged recently by a Zener polaron picture emerging from experiments and theoretical calculations. The effective low energy Hamiltonian for ...