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Simulation Of The Polarizable-Ion Dynamics Of Rb2Zncl4, P. J. Edwardson, John R. Hardy
Simulation Of The Polarizable-Ion Dynamics Of Rb2Zncl4, P. J. Edwardson, John R. Hardy
John R. Hardy Papers
The promotion yet prevention of structural stability in the paraelectric phase of Rb2ZnCl4 by ionic polarizability is explored with both constant-lattice and variable-lattice simulations. As many as 168 ions ( 3 x 1 x 2 cells) under periodic boundary constraints are allowed to polarize in nonlinear response to forces which are obtained from the electron-gas model of Gordon and Kim. No assumption about the rigidity of the ZnCl42- ion is made. The cause of polarization catastrophe in linear models is examined, and a cure is implemented via nonlinearity of the dipole moment versus field strength. …
Possible Origins Of High-TC, Superconductivity, John R. Hardy, J. W. Flocken
Possible Origins Of High-TC, Superconductivity, John R. Hardy, J. W. Flocken
John R. Hardy Papers
A new mechanism is proposed to explain high-Tc superconductivity in copper-oxide-based, open perovskitelike systems. It is shown that, should the oxygen ions be moving in a double-well potential, an order-of-magnitude enhancement of the electron-lattice coupling follows automatically from a consistent treatment of this motion. Both theoretical and experimental evidence for the presence of such double wells is cited.
Molecular-Dynamics Simulation Of The Structural Phase Transition In Rb2Cacl4, D. P. Billesbach, P. J. Edwardson, John R. Hardy
Molecular-Dynamics Simulation Of The Structural Phase Transition In Rb2Cacl4, D. P. Billesbach, P. J. Edwardson, John R. Hardy
John R. Hardy Papers
We have simulated the structural phase transition of one member of A2BX4 layered perovskite-like compounds, Rb2CaC14. This family of compounds may be thought of as being constructed from normal perovskite unit cells but with a different stacking arrangement. In recent months, this structural family has become extremely important since it is the parent structure from which the new class of high-temperature superconductors comes from. The simulation was done using ab initio potentials with no adjustable parameters. Our calculations show a specific-heat anomaly at 400 K which corresponds to an observed pseudorotation of the …