Charge transition levels of oxygen vacancies in monoclinic hafnia

ORAL

Abstract

We perform electronic structure calculations on oxygen vacancies in hafnia using a combined density functional theory (DFT) and GW formalism. This formalism corrects for the error in calculating formation energy and charge transition levels using standard DFT. While the formalism is, in principle, exact; in previous calculations of this kind, one makes several approximations to make the calculation tractable. We assess the impact of these approximations on the charge transition levels of the oxygen vacancy in hafnia. In particular, we examine the assumption that the quasiparticle wavefunctions are the same as DFT wavefunctions for the defect states. We show that this assumption can lead to erroneous results in this system and present the charge transition levels without making use of this assumption. We also explore the possibility that these defects are negative U centers.

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Authors

  • Manish Jain

    University of California, Berkeley and Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Lab, University of California at Berkeley and Lawrence Berkeley National Laboratory

  • James R. Chelikowsky

    University of Texas, University of Texas at Austin, UT Austin

  • Steven G. Louie

    University of California, Berkeley and Lawrence Berkeley National Laboratory, Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley National Lab, UC Berkeley, Department of Physics, U. C. Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, University of California-Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California at Berkeley, Phys Dept. UC Berkeley, Department of Physics, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, University of California at Berkeley and Lawrence Berkeley National Lab