Phonon spectra for Ta and W were calculated within a tight-binding approach. On the basis of these calculations the author showed that the (001) surface of Ta was stable while the W(001) surface was unstable with respect to distortions in the surface plane. The most unstable surface modes were in the vicinity of the M point, in agreement with experimental results and previous calculations. The author traces the destabilising forces to the peak in the surface electronic density of states, and conclude that the driving mechanism for reconstruction was mainly short range in nature.

A Tight-Binding Phonon Calculation to Investigate the (001) Surface Instability of Tungsten. D.P.Joubert: Journal of Physics C, 1988, 21[23], 4233-8