Reliability of Hybrid Functionals in Predicting Band Gaps

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Reliability of Hybrid Functionals in Predicting Band Gaps

Manish Jain, James R. Chelikowsky, and Steven G. Louie

Phys. Rev. Lett. 107, 216806 – Published 18 November 2011

Abstract

We show that orbital energies from existing hybrid functionals do not give reliable band gaps. Even if a functional yields a good bulk gap, it in general does not provide accurate gaps in different structural configurations, e.g., surfaces or nanostructures. For example, none of the popular hybrid functionals adequately describe the surface-state gap of the $Si (111) − (2 \times 1)$ surface. For graphene nanoribbons, some hybrid functionals give good optical gaps (neglecting strong excitonic effects), but not quasiparticle gaps. In both cases, there are strong variations from different hybrid functionals.

Received 28 June 2011

DOI:https://doi.org/10.1103/PhysRevLett.107.216806

Authors & Affiliations

Manish Jain^1,2, James R. Chelikowsky³, and Steven G. Louie^1,2

¹Department of Physics, University of California, Berkeley, California 94720, USA
²Materials Sciences Division, Lawrence Berkeley, National Laboratory, Berkeley, California 94720, USA
³Center for Computational Materials, Institute for Computational Engineering and Sciences, Departments of Physics and Chemical Engineering, University of Texas, Austin, Texas 78712, USA