The isostructural alpha-gamma phase transition in cerium from the perspective of meta-generalized gradient approximations
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| Format: | Preprint |
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2025
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| _version_ | 1866908392742715392 |
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| author | Giri, Ashesh Shahi, Chandra Ruzsinszky, Adrienn |
| author_facet | Giri, Ashesh Shahi, Chandra Ruzsinszky, Adrienn |
| contents | 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. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2506_03578 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The isostructural alpha-gamma phase transition in cerium from the perspective of meta-generalized gradient approximations Giri, Ashesh Shahi, Chandra Ruzsinszky, Adrienn Materials Science 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. |
| title | The isostructural alpha-gamma phase transition in cerium from the perspective of meta-generalized gradient approximations |
| topic | Materials Science |
| url | https://arxiv.org/abs/2506.03578 |