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Professor Stewart Clark's Outputs (18)

Condensed phase ionic polarizabilities from plane wave density functional theory calculations (2006)
Journal Article
Heaton, R. J., Madden, P. A., Clark, S. J., & Jahn, S. (2006). Condensed phase ionic polarizabilities from plane wave density functional theory calculations. The Journal of Chemical Physics, 125(14), Article 144104. https://doi.org/10.1063/1.2357151

A method is presented to allow the calculation of the dipole polarizabilities of ions and molecules in a condensed-phase coordination environment. These values will be useful for understanding the optical properties of materials and for developing si... Read More about Condensed phase ionic polarizabilities from plane wave density functional theory calculations.

Lattice dynamics of polyaniline and poly(p-pyridyl vinyline): First-principles determination (2006)
Journal Article
Zheng, G., Clark, S., Brand, S., & Abram, R. (2006). Lattice dynamics of polyaniline and poly(p-pyridyl vinyline): First-principles determination. Physical review B, 74(16), https://doi.org/10.1103/physrevb.74.165210

First-principles density functional studies of the dynamical properties of the conjugated polymers polyaniline and poly(p-pyridyl vinyline) are presented in this work. We have employed linear response within density functional perturbation theory, as... Read More about Lattice dynamics of polyaniline and poly(p-pyridyl vinyline): First-principles determination.

Defect states in the high-dielectric-constant gate oxide LaAlO3 (2006)
Journal Article
Xiong, K., Robertson, J., & Clark, S. (2006). Defect states in the high-dielectric-constant gate oxide LaAlO3. Applied Physics Letters, 89(2), Article 022907. https://doi.org/10.1063/1.2221521

We present calculations of the energy levels of the oxygen vacancy,AlLa antisite, and oxygen interstitial defects in LaAlO3 using density functional methods that do not need an empirical band gap correction. The levels are aligned to those of the Si... Read More about Defect states in the high-dielectric-constant gate oxide LaAlO3.

Variational density-functional perturbation theory for dielectrics and lattice dynamics (2006)
Journal Article
Refson, K., Tulip, P., & Clark, S. (2006). Variational density-functional perturbation theory for dielectrics and lattice dynamics. Physical review B - Condensed Matter and Materials Physics, 73(15), Article 155114. https://doi.org/10.1103/physrevb.73.155114

The application of variational density functional perturbation theory (DFPT) to lattice dynamics and dielectric properties is discussed within the plane-wave pseudopotential formalism. We derive a method to calculate the linear response of the exchan... Read More about Variational density-functional perturbation theory for dielectrics and lattice dynamics.

Molecular dynamics calculations of the thermal expansion properties and melting points of Si and Ge (2006)
Journal Article
Timon, V., Brand, S., Clark, S., & Abram, R. (2006). Molecular dynamics calculations of the thermal expansion properties and melting points of Si and Ge. Journal of Physics: Condensed Matter, 18(13), 3489-3498. https://doi.org/10.1088/0953-8984/18/13/016

The thermal expansion properties and melting points of silicon and germanium are calculated using molecular dynamics simulations within the density functional theory framework. An isothermal–isobaric (NPT) ensemble is considered in a periodic system... Read More about Molecular dynamics calculations of the thermal expansion properties and melting points of Si and Ge.

Matrix dependence of blue light emission from a novel NH2-functionalized dicyanoquinodimethane derivative (2006)
Journal Article
Szablewski, M., Bloor, D., Kagawa, Y., Mosurkal, R., Cole, J., Clark, S., …Palsson, L. (2006). Matrix dependence of blue light emission from a novel NH2-functionalized dicyanoquinodimethane derivative. Journal of Physical Organic Chemistry, 19(3), 206-213. https://doi.org/10.1002/poc.1020

The reactions of primary and secondary amines with (cyclohexa-2,5-diene-1,4-diylidene)-dimalononitrile (TCNQ) lead to mono- and disubstituted dicyanoquinodimethane derivatives and fluorescence emission has been observed for several of these compounds... Read More about Matrix dependence of blue light emission from a novel NH2-functionalized dicyanoquinodimethane derivative.

Passivation of oxygen vacancy states in HfO2 by nitrogen (2006)
Journal Article
Xiong, K., Robertson, J., & Clark, S. (2006). Passivation of oxygen vacancy states in HfO2 by nitrogen. Journal of Applied Physics, 99(4), Article 044105. https://doi.org/10.1063/1.2173688

Nitrogen is known to reduce leakage currents and charge trapping in high-dielectric-constant gate oxides such as HfO2. We show that this occurs because nitrogen, substituting for oxygen atoms next to oxygen vacancy sites, repels the occupied gap stat... Read More about Passivation of oxygen vacancy states in HfO2 by nitrogen.