PERIODIC LATTICE-DISTORTIONS AND CHARGE-DENSITY WAVES IN ONE-DIMENSIONAL AND 2-DIMENSIONAL METALS

At low temperatures, low-dimensional metals are commonly found to exhibit superlattices incommensurate with the primitive lattice (periodic lattice distortion coupled to charge density waves, PLD-CDW). Transitions to such states are driven by strong electron-phonon coupling and favoured by the particular forms of the Fermi surface in these metals. Experimental investigations of the structural distortions, and of the changes in electronic structure around the Fermi level produced by the PLD-CDW state, will be discussed for the layered dichalcogenides, the linear chain platinum complex KCP, and the organic charge transfer salts.