Spatial structure formation in charge density wave systems

Besides the superlattice with the period equal to twice the Fermi wave vect or q = 2k(F), charge density waves (CDW) also show a spatial structure form ation with a length scale much larger than the period of the superlattice. Following the theory of Fukuyama, Lee, and Rice (FLR), values of some micro ns are expected for the extension of the FLR domains. We have performed inv estigations with a low-temperature scanning electron microscope (SEM) on K0 .30MoO3 and TaS3, in order to visualize these domain-like structures: In co ntrast to the usual SEM methods, we recorded the electric response (e.g., t he thermovoltage) of the sample in dependence of the beam position. The ana lysis of the images obtained reveals values for different parameters that w ell agree with the ones obtained by other methods. (C) 1999 Elsevier Scienc e S.A. All rights reserved.