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## Local volume effects in the generalized pseudopotential theory

## Abstract

The generalized pseudopotential theory (GPT) is a compelling approach for deriving real-space transferable interatomic potentials. Using a coarse-grained electronic structure, one can explicitly determine the pair ion-ion and multi-ion interactions in simple and transition metals. While successful in determining bulk properties, in central force metals the GPT fails to describe crystal defects for which there is a significant local volume change. A previous paper [J. A. Moriarty and R. Phillips, Phys. Rev. Lett. 66, 3036 (1991)] found that by allowing the GPT total energy to depend upon some spatially averaged local electron density, the energetics of vacancies and surfaces could be calculated within experimental ranges. In this paper, we develop the formalism further by explicitly calculating the forces and stress tensor associated with this total energy. We call this scheme the adaptive GPT (aGPT) and it is capable of both molecular dynamics (MD) and molecular statics. We apply the aGPT to vacancy formation, divacancy binding, and stacking faults in hcp Mg. We also calculate the local electron density corrections to the bulk elastic constants and phonon dispersion for which there is refinement over the baseline GPT treatment. Furthermore, we demonstrate aGPT-MD simulation through the calculation of thermal expansion in magnesiummore »

- Authors:

- King's College London (United Kingdom)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

- Publication Date:

- Research Org.:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA)

- OSTI Identifier:
- 1557065

- Report Number(s):
- LLNL-JRNL-761045

Journal ID: ISSN 2469-9950; PRBMDO; 949102

- Grant/Contract Number:
- AC52-07NA27344

- Resource Type:
- Accepted Manuscript

- Journal Name:
- Physical Review B

- Additional Journal Information:
- Journal Volume: 99; Journal Issue: 21; Journal ID: ISSN 2469-9950

- Publisher:
- American Physical Society (APS)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

### Citation Formats

```
Skinner, Guy C. G., Paxton, Anthony T., and Moriarty, John A. Local volume effects in the generalized pseudopotential theory. United States: N. p., 2019.
Web. doi:10.1103/PhysRevB.99.214107.
```

```
Skinner, Guy C. G., Paxton, Anthony T., & Moriarty, John A. Local volume effects in the generalized pseudopotential theory. United States. doi:10.1103/PhysRevB.99.214107.
```

```
Skinner, Guy C. G., Paxton, Anthony T., and Moriarty, John A. Wed .
"Local volume effects in the generalized pseudopotential theory". United States. doi:10.1103/PhysRevB.99.214107.
```

```
@article{osti_1557065,
```

title = {Local volume effects in the generalized pseudopotential theory},

author = {Skinner, Guy C. G. and Paxton, Anthony T. and Moriarty, John A.},

abstractNote = {The generalized pseudopotential theory (GPT) is a compelling approach for deriving real-space transferable interatomic potentials. Using a coarse-grained electronic structure, one can explicitly determine the pair ion-ion and multi-ion interactions in simple and transition metals. While successful in determining bulk properties, in central force metals the GPT fails to describe crystal defects for which there is a significant local volume change. A previous paper [J. A. Moriarty and R. Phillips, Phys. Rev. Lett. 66, 3036 (1991)] found that by allowing the GPT total energy to depend upon some spatially averaged local electron density, the energetics of vacancies and surfaces could be calculated within experimental ranges. In this paper, we develop the formalism further by explicitly calculating the forces and stress tensor associated with this total energy. We call this scheme the adaptive GPT (aGPT) and it is capable of both molecular dynamics (MD) and molecular statics. We apply the aGPT to vacancy formation, divacancy binding, and stacking faults in hcp Mg. We also calculate the local electron density corrections to the bulk elastic constants and phonon dispersion for which there is refinement over the baseline GPT treatment. Furthermore, we demonstrate aGPT-MD simulation through the calculation of thermal expansion in magnesium to 700 K.},

doi = {10.1103/PhysRevB.99.214107},

journal = {Physical Review B},

number = 21,

volume = 99,

place = {United States},

year = {2019},

month = {6}

}

Works referenced in this record:

##
Accurate and simple analytic representation of the electron-gas correlation energy

journal, June 1992

- Perdew, John P.; Wang, Yue
- Physical Review B, Vol. 45, Issue 23, p. 13244-13249