Formation energy puzzle in intermetallic alloys: Random phase approximation fails to predict accurate formation energies
| Autor: | Santosh Adhikari, Niraj K. Nepal, Adrienn Ruzsinszky, Bimal Neupane |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Physics
Condensed Matter - Materials Science Valence (chemistry) Alloy Intermetallic Binary number Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology 01 natural sciences Molecular physics Error cancellation Generalized gradient Condensed Matter::Materials Science 0103 physical sciences Density of states engineering Physics::Atomic and Molecular Clusters 010306 general physics 0210 nano-technology Random phase approximation |
| Popis: | We performed density-functional calculations to estimate the formation energies of intermetallic alloys. We used two semilocal approximations, the generalized gradient approximation (GGA) by Perdew-Burke-Ernzerhof (PBE), and the strongly constrained and appropriately normed (SCAN) meta-GGA. In addition, we utilized two nonlocal DFT functionals, the hybrid HSE06, and the state-of-the-art random phase approximation (RPA). The nonlocal functionals such as HSE06 and RPA yield accurate formation energies of binary alloys with completely filled $d$-band metals, where semilocal functionals underperform. The accuracy of the nonlocal functionals is greatly reduced when a partially filled $d$-band metal is present in an alloy, while PBE-GGA outperforms in these cases. We show that the accurate prediction of formation energies by any DFT method depends on its ability to predict the accurate electronic properties, e.g., valence $d$-band contribution to the density of states (DOS). The SCAN meta-GGA often corrects the PBE-DOS, however, it does not provide accurate formation energies compared to PBE. This is assumed to be due to the lack of proper error cancellation that should be expected due to the similar bulk nature of both alloys and their constituents, which may improve with the modification of meta-GGA ingredients. RPA yields too-negative formation energies of alloys with partially filled $d$-band metals. RPA results can be corrected by restoring the exchange-correlation kernel, thereby improving the short-range electron-electron correlation in metallic densities. |
| Databáze: | OpenAIRE |
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