THE POSSIBLE MECHANISM OF INCOMMENSURATE CHARGE-DENSITY-WAVE OCCURRENCE ON THE (100)W SURFACE

The results of the tight-binding calculations of the conduction electr ons contribution to the dynamical matrix are presented, The analysis o f the elements of dynamical matrix shows that the maximum instability of the M(5) surface phonon mode is explained by the low dispersion of the surface states bands near the E(F) and the strong wave vector depe ndence of the matrix elements of the electron-phonon interactions. The calculations for a nonzero temperature indicated deviations of the ma ximum from the M point due to different temperature dependence of the intraband and interband contributions to the dynamical matrix. It is a ssumed that this is the reason for the incommensurate periodic lattice distortion occurrence on the (100)W surface.