2025/06/04 by Ashesh Giri, Giri, Ashesh, Chandra Shahi +3
Materials Science · Physics and Astronomy · #Cerium #Delocalized electron #Density functional theory #Electron #Electronic structure #FOS: Physical sciences #Hybrid functional #Hydrogen Storage and Materials #Isostructural #Materials Science (cond-mat.mtrl-sci) #Nuclear Materials and Properties #Phase transition #Rare-earth and actinide compounds
paper · pdf · doi:10.48550/arxiv.2506.03578
openalex publication_date 2025/06/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Meta-generalized gradient approximations (meta-GGAs) on the third rung of the functional hierarchy are gaining increasing relevance for the electronic structure. Meta-GGAs are constructed from numerous ingredients including the orbital kinetic energy density that make them more flexible than generalized gradient approximations (GGAs) including the heavily used PBE-GGA. Still, most meta-GGAs cope with the expected limitations of a semilocal density functional when band gaps or localization of electrons are needed. On the other hand, meta-GGAs are implicit functionals of the orbitals. This feature resembles hybrid density functionals with exact exchange. Efforts in recent years demonstrate that some meta-GGAs can rise beyond the accuracy of semilocal approximation when band gaps are computed. Cerium is an ideal testbed to challenge some recent meta-GGAs. Cerium shows an isostructural alpha - gamma phase transition with delocalized and localized f electrons in each phase, respectively. Since the phonon entropy term was found negligible in the alpha - gamma phase transition of cerium by accurate experiments, all changes in the transition are driven by electronic correlation. The correlation of f electron systems is hardly captured by semilocal approximations but the recent LAK meta-GGA with ultranonlocality steps out of the framework of conventional semilocal density functionals and delivers spectacular accuracy for the phase transition of cerium. LAK and further meta-GGAs inspired by the success of LAK can open a forefront of meta-GGAs for quantum materials with localized electrons.