# Parallel empirical pseudopotential electronic structure calculations for million atom systems

## Abstract

The authors present a parallel implementation of the previously developed folded spectrum method for empirical pseudopotential electronic calculations. With the parallel implementation the authors can calculate a small number of electronic states for systems of up to one million atoms. A plane-wave basis is used to expand the wavefunctions in the same way as is commonly used in ab initio calculations, but the potential is a fixed external potential generated using atomistic empirical pseudopotentials. Two techniques allow the calculation to scale to million atom systems. First, the previously developed folded spectrum method allows them to calculate directly a few electronic states of interest around the gap. This makes the scaling of the calculation O(N) for an N atom system and a fixed number of electronic states. Second, they have now developed an efficient parallel implementation of the algorithm that scales up to hundreds of processors, giving them the memory and computer power to simulate one million atoms. The program's performance is demonstrated for many large semiconductor nanostructure systems.

- Authors:

- Publication Date:

- Research Org.:
- Lawrence Berkeley National Lab, CA (US)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 20030414

- DOE Contract Number:
- AC36-99GO10337; AC03-76SF00098

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Computational Physics

- Additional Journal Information:
- Journal Volume: 160; Journal Issue: 1; Other Information: PBD: 1 May 2000; Journal ID: ISSN 0021-9991

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 36 MATERIALS SCIENCE; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ELECTRONIC STRUCTURE; SEMICONDUCTOR MATERIALS; PARALLEL PROCESSING; ALGORITHMS; CALCULATION METHODS; WAVE FUNCTIONS

### Citation Formats

```
Canning, A., Wang, L.W., Williamson, A., and Zunger, A.
```*Parallel empirical pseudopotential electronic structure calculations for million atom systems*. United States: N. p., 2000.
Web. doi:10.1006/jcph.2000.6440.

```
Canning, A., Wang, L.W., Williamson, A., & Zunger, A.
```*Parallel empirical pseudopotential electronic structure calculations for million atom systems*. United States. doi:10.1006/jcph.2000.6440.

```
Canning, A., Wang, L.W., Williamson, A., and Zunger, A. Mon .
"Parallel empirical pseudopotential electronic structure calculations for million atom systems". United States. doi:10.1006/jcph.2000.6440.
```

```
@article{osti_20030414,
```

title = {Parallel empirical pseudopotential electronic structure calculations for million atom systems},

author = {Canning, A. and Wang, L.W. and Williamson, A. and Zunger, A.},

abstractNote = {The authors present a parallel implementation of the previously developed folded spectrum method for empirical pseudopotential electronic calculations. With the parallel implementation the authors can calculate a small number of electronic states for systems of up to one million atoms. A plane-wave basis is used to expand the wavefunctions in the same way as is commonly used in ab initio calculations, but the potential is a fixed external potential generated using atomistic empirical pseudopotentials. Two techniques allow the calculation to scale to million atom systems. First, the previously developed folded spectrum method allows them to calculate directly a few electronic states of interest around the gap. This makes the scaling of the calculation O(N) for an N atom system and a fixed number of electronic states. Second, they have now developed an efficient parallel implementation of the algorithm that scales up to hundreds of processors, giving them the memory and computer power to simulate one million atoms. The program's performance is demonstrated for many large semiconductor nanostructure systems.},

doi = {10.1006/jcph.2000.6440},

journal = {Journal of Computational Physics},

issn = {0021-9991},

number = 1,

volume = 160,

place = {United States},

year = {2000},

month = {5}

}