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Potential Energy Surfaces for H Adsorbed at 4H-SiC{0001} Surfaces

100%

Wachowicz E., Kiejna A.

Acta Physica Polonica A

2013

vol. 124

issue 5

765-767

The constant adsorption energy surfaces for hydrogen adsorbed on Si- and C-terminated hexagonal 4H-SiC{0001} surfaces have been calculated within density functional theory framework. The two unreconstructed and one reconstructed √3 × √3 surfaces were taken into account. We show that on all surfaces there is a global energy minimum indicating the most favourable adsorption site corresponding to H atom adsorption on-top of the topmost substrate layer atom. In case of reconstructed surface, there is another small and shallow local minimum. Moreover, the diffusion barrier is much higher at reconstructed surface than at unreconstructed ones.

Ab initio Calculations of Phonon Dispersion Relations in Aluminium

81%

Scharoch P., Parliński K., Kiejna A.

Acta Physica Polonica A

2000

vol. 97

issue 2

349-354

A direct method and ab initio force constants were used to calculate phonon dispersion curves and phonon density in Al. The force constants were determined from the Hellmann-Feynman forces induced by the displacement of an atom in the 2×2×2 fcc crystallographic supercell. This size of the supercell gives exact phonon frequencies at Γ, X, L, W points of the Brillouin zone. The calculated phonon dispersion curves are in good agreement with the experimental data.

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2 Acta Physica Polonica A

1 2013

1 2000

2 Kiejna A.

1 Parliński K.

1 Scharoch P.

1 Wachowicz E.

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Potential Energy Surfaces for H Adsorbed at 4H-SiC{0001} Surfaces

Ab initio Calculations of Phonon Dispersion Relations in Aluminium