title: Comparison of the Kubo formula, the microscopic response method, and the Greenwood formula.
abstract: For a mechanical perturbation, the microscopic response method is equivalent to and more convenient to use than the Kubo formula. When the gradient of the carrier density is small, the current density reduces to that used by Greenwood.
authors.affiliation: Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA.
authors.forename: Mingliang
authors.initials: M
authors.lastname: Zhang
authors.forename: D A
authors.initials: DA
authors.lastname: Drabold