Development of a tight-binding potential for bcc Zr: Application to the study of vibrational properties - art. no. 134104

We present a tight-binding potential based on the moment expansion of the d ensity of states, which includes up to the fifth moment. The potential is f itted to bcc and hcp Zr and it is applied to the computation of vibrational properties of bcc Zr. In particular, we compute the isothermal elastic con stants in the temperature range 1200 K<T<2000 K by means of standard Monte Carlo simulation techniques. The agreement with experimental results is sat isfactory, especially in the case of the stability of the lattice with resp ect to the shear associated with C'. However, the temperature decrease of t he Cauchy pressure is not reproduced. The T = 0 K phonon frequencies of bcc Zr are also computed. The potential predicts several instabilities of the bcc structure, and a crossing of the longitudinal and transverse modes in t he (001) direction. This is in agreement with recent ab initio calculations in Sc, Ti, Hf, and La.