Charge Density Waves (CDWs) occur due to a reconfiguration of both the electronic and lattice structures as a result of the interactions of the electrons with both themselves, and the lattice. Given that a certain amount of coupling between electrons and phonons exists, the phonon dispersion will undergo a strong change at lower temperatures. This causes the phonon mode to form a standing wave, (that is to say, a certain nonzero wavevector of energy zero.) Consequently, the electron density, which is coupled to the phonon density also undergoes oscillations. The CDW state occurs when such a reconfiguration is energetically preferable.

     Even though an exact, overlapping model for CDW occurence from any mechanism, and of any dimensionality is yet elusive, a simple 1D model exists that illustrates the CDW occurence at \(T=0K\). Following the derivation proposed in the work by Rossnagel [1], which closely follows the mean-field theory approach taken by Gruner [2], an electronic susceptibility can be extracted.