2015 Fiscal Year Annual Research Report
First-principle device simulation
| Project/Area Number |
15H06889
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| Research Institution | National Institute of Advanced Industrial Science and Technology |
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Principal Investigator |
Buerkle Marius 国立研究開発法人産業技術総合研究所, 材料・化学領域 機能材料コンピュテーショナルデザイン研究センター, 研究員 (00756661)
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| Project Period (FY) |
2015-08-28 – 2017-03-31
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| Keywords | thermoelectrics / dft / negf |
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| Outline of Annual Research Achievements |
The nonequilibrium green’s function (NEGF) method developed by us was implemented for linear response regime and validated. The electronic structure is obtained within density functional theory (DFT). Currently the method is applied to various systems including:
1.) Carbon based devices: Graphene+polymer+Graphene junctions. Here we investigate he intermediate regime between tunneling and hopping regime and investigate the respective length dependence.
2.) Metallica nanowires with diameters of ranging from several nano meters to atomic constrictions. Here we focuse on the possibility to electrochemical gate the system.
3.) 1D Systems: like atomic wires and carbon nanotubes. Here especially the phonons are of interest as the scattering confined in 1 dimension.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
1.) Implementation progresses as planned.
2.) Productive calculations are still ongoing.
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| Strategy for Future Research Activity |
The next stage, phase 2, targets to implement additional features into the transport code:
1.) finite bias calculations using non-SC-NEGF and full SCF-NEGF. The implementation will go along the lines of including the external potential by means if green's functions, hence avoiding an explicit solution of the poisson equation for systems with broken translational invariance.
2.) Increase the feasible systems size for both DFT and NEGF calculation, by i. improving the DFT code, ii. introducing MPI and divide and conquer schemes for the NEGF calculations, and iii. parallelized integration schemes for the density integration at finite bias.
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