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Ensemble density-functional theory for ab-initio molecular dynamics of metals and finite-temperature insulators

Nicola Marzari·David Vanderbilt·M. C. Payne
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Abstract

A new method is presented for performing first-principles molecular-dynamics simulations of systems with variable occupancies. We adopt a matrix representation for the one-particle statistical operator Gamma, to introduce a ``projected'' free energy functional G that depends on the Kohn-Sham orbitals only and that is invariant under their unitary transformations. The Liouville equation [ Gamma , H ] = 0 is always satisfied, guaranteeing a very efficient and stable variational minimization algorithm that can be extended to non-conventional entropic formulations or fictitious thermal distributions.

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Nicola Marzari, David Vanderbilt, M. C. Payne. 1997-03-08. Ensemble density-functional theory for ab-initio molecular dynamics of metals and finite-temperature insulators. https://doi.org/10.1103/physrevlett.79.1337

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