2018/04/30 by Luning Zhao, Eric Neuscamman · 19 citations
Materials Science · Mathematics · Physics and Astronomy · #Advanced Chemical Physics Studies #Computer science #Excited state #Exploit #Mathematics #Monte Carlo method #Perturbation (astronomy) #Perturbation theory (quantum mechanics) #Physics #Physics of Superconductivity and Magnetism #Quantum Monte Carlo #Quantum mechanics #Statistical physics #Theoretical physics #Wave function #ZnO doping and properties #cond-mat.str-el #physics.chem-ph
paper · pdf · doi:10.1103/physrevlett.123.036402
published in Physical Review Letters 123(3), 036402 (American Physical Society) · 8 pages, 5 figures, 2 tables
arxiv created 2019/06/17 · openalex publication_date 2019/07/16 · arxiv updated 2019/07/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present an approach to studying optical band gaps in real solids in which quantum Monte Carlo methods allow for the application of a rigorous variational principle to both ground and excited state wave functions. In tests that include small, medium, and large band gap materials, optical gaps are predicted with a mean absolute deviation of 3.5% against experiment, less than half the equivalent errors for typical many-body perturbation theories. The approach is designed to be insensitive to the choice of density functional, a property we exploit in order to provide insight into how far different functionals are from satisfying the assumptions of many-body perturbation theory. We explore this question most deeply in the challenging case of ZnO, where we show that, although many commonly used functionals have shortcomings, there does exist a one-particle basis in which perturbation theory's zeroth-order picture is sound. Insights of this nature should be useful in guiding the future application and improvement of these widely used techniques.