Crystal momentum

In solid-state physics, crystal momentum or quasimomentum is a momentum-like vector associated with electrons in a crystal lattice. It is defined by the associated wave vectors ${\displaystyle \mathbf {k} }$ of this lattice, according to

${\displaystyle {\mathbf {p} }_{\text{crystal}}\equiv \hbar {\mathbf {k} }}$

(where ${\displaystyle \hbar }$ is the reduced Planck's constant).^: 139 Frequently, crystal momentum is conserved like mechanical momentum, making it useful to physicists and materials scientists as an analytical tool.