GRAZING-INCIDENCE X-RAY STUDY OF THE CHARGE-DENSITY-WAVE PHASE-TRANSITION IN K0.3MOO3

The charge-density-wave (CDW) phase transition has been studied for a range of depth of 20 10000 below the (201») surface of K0.3MoO3 by use of grazing-incidence x-ray diffraction. It is found that the CDW wave vector is the same as in the bulk. The transition temperature as well as the temperature dependence of the order parameter (down to 125 K) appear to be independent of the depth probed by the x-ray beam. The fact that the surface does not appear to modify the characteristics of the CDW in this particular case is probably related to the weak coupling between the slabs of MoO6 octahedra, perpendicular to the (201») surface. © 1990 The American Physical Society.