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1

Nanoscale Deformation of GaAs Affected by Silicon Doping

100%

Majtyka A., Nowak R., Chrobak D.

Acta Physica Polonica A

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2016

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vol. 130

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issue 4

1127-1130

EN

Effect of silicon doping on the elastic-plastic transition of GaAs crystal is demonstrated by results of nanoindentations and ab initio simulations. The performed experiments show that an increase of silicon concentration causes a decrease of the contact pressure at the onset of permanent nanodeformation of GaAs crystal. Ab initio calculations demonstrate that presence of Si atoms in the crystal lattice suppresses the shear modulus as well as the pressure of equilibrium between zinc-blende and rock-salt phases of GaAs. Furthermore, it is argued that the effect of dislocations pinning to Si dopants is essential for clarification of GaAs yielding.

2

Electronic Structure of Sm(Ni_{1-x}Co_{x})₃ Alloys - XPS and ab initio Study

88%

Majtyka A., Sikora M., Blachiński D., Chełkowska G., Deniszczyk J.

Acta Physica Polonica A

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2018

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vol. 133

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issue 3

673-675

EN

The band structure investigations for Sm(Ni_{1-x}Co_{x})₃ alloys by means of X-ray photoelectron spectroscopy (XPS) and an ab initio density functional theory (DFT) calculations are presented. The aim was to determine an effect of Ni/Co substitution on the electronic structure of the alloys. Investigations have shown that the Ni/Co substitution results in a reconstruction of the valence band (VB), especially the intensity near the Fermi level decreases with Co content. An ab initio simulated XPS VB spectra agree qualitatively with experimental ones with the exception of the Sm-4f sub-spectra where the multiplet decomposition is observed. Calculations shown that variation of magnetization in Sm(Ni_{1-x}Co_{x})₃ is driven mainly by the Ni/Co-3d and Sm-5d states polarization and increases linearly with rising Co content.

3

Elastic-Plastic Transition in MBE-Grown GaSb Semiconducting Crystal Examined by Nanoindentation

76%

Majtyka A., Trębala M., Tukiainen A., Chrobak D., Borgieł W., Räisänen J., Nowak R.

Acta Physica Polonica A

|

2016

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vol. 130

|

issue 4

1131-1133

EN

The present paper concerns the elastic-plastic nanodeformation of Te-doped GaSb crystals grown by molecular beam epitaxy on the n-type of GaSb substrate. The conventional analysis of nanoindentation data obtained with sharp triangular (Berkovich) and spherical tip revealed the elastic modulus (E=83.07± 1.78 GPa), hardness (H=5.19±0.25 GPa) and "true hardness" (H_{T}=5.73±0.04 GPa). The registered pop-in event which indicates the elastic-plastic transition in GaSb crystal points towards the corresponding yield strength (σ_{Y}=3.8±0.1 GPa). The origin of incipient plasticity in GaSb crystal is discussed in terms of elastic-plastic deformation energy concept.

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3 Acta Physica Polonica A

1 2018

2 2016

3 Majtyka A.

2 Chrobak D.

2 Nowak R.

1 Blachiński D.

1 Borgieł W.

1 Chełkowska G.

1 Deniszczyk J.

1 Räisänen J.

1 Sikora M.

1 Trębala M.

1 Tukiainen A.

Nanoscale Deformation of GaAs Affected by Silicon Doping

Electronic Structure of Sm(Ni_{1-x}Co_{x})₃ Alloys - XPS and ab initio Study

Elastic-Plastic Transition in MBE-Grown GaSb Semiconducting Crystal Examined by Nanoindentation