Fermi surface nesting

Fermi surface nesting is a phenomenon in condensed matter physics in which two or more approximately parallel sections of a Fermi surface can be mapped onto one another by a common wave vector $\mathbf {Q}$. The resulting geometric relationship between different portions of the Fermi surface can enhance the electronic response at the corresponding wave vector and may promote instabilities such as charge-density waves (CDWs), spin-density waves (SDWs), and, in some systems, structural phase transitions.