The existence of anharmonic localization of lattice vibrations in a perfect 3-D diatomic ionic crystal is established for the rigid-ion model by molecular dynamics simulations. For a realistic set of NaI potential parameters, an intrinsic localized gap mode vibrating in the [111] direction is observed for fcc and zinc blende lattices. An axial elastic distortion is an integral feature of this mode which forms more readily for the zinc blende than for the fcc structure. Molecular dynamics simulations verify that in each structure this localized mode may be stable for at least 200 cycles. |

- Introduction
- Dynamical Simulated Annealing
- Rigid-ion Model of Ionic Crystal
- Eigenvectors (Figures)
- [111] Mode Eigenvector in FCC Structure (Java Applet)
- [111] Mode Eigenvector in FCC Structure, [100] Plane (Java Applet)
- [111] Mode Eigenvector in Zinc Blende Structure (Java Applet)
- [110] Mode Eigenvector in Zinc Blende Structure (Java Applet)
- Molecular-Dynamics Simulations Tests
- Frequency vs. Amplitude Dependence
- Conclusions
- Acknowledgments