Theory of Condensed Matter, Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE, U.K.
We present a new method for the calculation of ground-state total energies within density-functional theory, based upon the single-particle density-matrix formulation, which requires a computational effort which scales only linearly with system-size. The difficult idempotency constraint is imposed approximately using a penalty-functional constructed to allow efficient minimization. The resulting error in the total energy due to the violation of idempotency is removed by an analytic correction. The results for a system comprising 216 atoms of crystalline silicon are compared with those from a standard plane-wave code. Linear scaling to 512 atoms is also demonstrated on a workstation.
PACS numbers: 71.15.Mb