Anomalous phonon behavior and phase fluctuations in bcc Zr

B. L. Zhang , C. Z. Wang , K. M. Ho , D. Turner , Y. Y. Ye

Physical Review Letters Vol. 74, No. 8, 1375-1378 (20 February 1995).

          The high-temperature bcc phase of Zr is simulated by molecular dynamics using an embedded-atom potential. Our results show strong asymmetric scattering cross sections in different Brillouin zones, in agreement with inelastic neutron scattering experiments. This anomalous behavior arises from fluctuations between the bcc and hcp phases. The phase fluctuations produce large anharmonic contributions to the dynamical structure factors, which are not predicted by traditional phonon theory.