Lattice dynamics ofNd2CuO4
| Autor: | Winfried Kress, E. Rampf, F. W. de Wette, U. Schröder, Anil D. Kulkarni |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Physical Review B. 48:10143-10152 |
| ISSN: | 1095-3795 0163-1829 |
| Popis: | We present a lattice-dynamical treatment of ${\mathrm{Nd}}_{2}$${\mathrm{CuO}}_{4}$ (T' structure) in the framework of a shell model that is based on short-range overlap and long-range Coulomb potentials, and includes ionic polarizabilities. We have formulated the static equilibrium conditions for the T' structure under this interaction model, and use the equilibrium conditions to determine the potential parameters for some of the unknown short-range interactions (e.g., Nd-O). Two versions of the shell model are used in the calculation: model I (``generic'' model), which was developed without reference to any experimental phonon-dispersion data of ${\mathrm{Nd}}_{2}$${\mathrm{CuO}}_{4}$, and model II, which involved some fitting to the experimental data. In addition to the phonon-dispersion curves, we present results for the phonon density of states F(\ensuremath{\omega}) and the phonon specific heat ${\mathit{c}}_{\mathit{v}}$(T). We discuss the low-temperature behavior of ${\mathit{c}}_{\mathit{v}}$(T) by examining ${\mathit{c}}_{\mathit{v}}$(T)/${\mathit{T}}^{3}$ and FTHETA(T) in the range between 0 and 40 K. |
| Databáze: | OpenAIRE |
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