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Reconciling Ionization Energies and Band Gaps of Warm Dense Matter \\Derived with {\it Ab Initio} Simulations and Average Atom Models

Massacrier, G.; Böhme, M.; Vorberger, J.; Soubiran, F.; Militzer, B.

Average atom (AA) models allow one to efficiently compute electronic and optical properties of materials over a wide range of conditions and are thus often employed to interpret experimental data. However, at high pressure, predictions from AA models have been shown to disagree with results from many-body {\it ab initio} computer simulations. Here we reconcile these deviations by developing an innovative type of AA model, \Avion, that computes the electronic eigenstates with novel boundary conditions within the ion sphere. Bound and free states are thus derived consistently. We drop the common AA assumption that the free-particle spectrum starts at the potential threshold, which we found to be incompatible with {\it ab initio} calculations. We perform {\it ab initio} simulations of crystalline and liquid carbon and aluminum over a wide range of densities and show that the computed band structure is in very good agreement with predictions from \Avion.

Keywords: Warm Dense Matter; Ab initio; density functional theory; molecular dynamics; average atom; High Energy Density; ionization potential depression

Related publications

  • Open Access Logo Physical Review Research 3(2021), 023026
    DOI: 10.1103/PhysRevResearch.3.023026
  • Lecture (Conference) (Online presentation)
    APS March Meeting 2021, 15.-19.03.2021, Washington DC, USA

Permalink: https://www.hzdr.de/publications/Publ-31149
Publ.-Id: 31149