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1

Ab-initio calculation of band structure and linear optical properties of SbSI in para- and ferroelectric phases

100%

Akkus H., Mamedov A.

Open Physics

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2007

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vol. 5

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issue 1

25-34

EN

An ab-initio pseudopotential calculation has been performed by using density functional methods within the local density approximation (LDA) to investigate the band structure and optical properties of the ferroelectric-semiconductor SbSI in the para- and ferroelectric phases. It has been shown that SbSI has an indirect gap in both phases (1.45 eV and 1.49 eV in the para- and ferroelectric phases respectively) and that the smallest direct gap is at the S point of the Brillouin zone (1.56 eV and 1.58 eV in the para- and ferroelectric phases respectively). Furthermore, it is shown that first-order phase transition, from the paraelectric phase to the ferroelectric phase (the transiton temperature is about 22 °C), does not change the nature of the band gap. Moreover, the linear frequency dependent dielectric function, including self-energy effects, has been calculated along the c-polar axis in the para- and ferroelectric phases.

2

Wave Propagation in a LRPC Composite Double Panel Structure with Periodically Attached Pillars and Etched Holes

75%

Qian D.

Archives of Acoustics

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2018

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vol. 43

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issue 4

3

Theoretical investigation of the electronic structure of a ferroelectric SbSI cluster at a phase transition

63%

Audzijonis A., Gaigalas G., Žigas L., Pauliukas A., Žaltauskas R., Čerškus A., Narusis J.

Open Physics

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2005

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vol. 3

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issue 3

382-394

EN

This paper presents the theoretical investigation of energy levels of valence bands (VB) and core levels (CL) of the ferroelectric SbSl single crystals in antiferroelectric and ferroelectric phases. Since the best approximation for the deep VB levels is a calculation by the Hartree-Fock method, the molecular model of a SbSI crystal was used for calculations. This model of the crystal was also used for calculations of the total density of states. It was found that the VB and CL of this ferroelectric semiconductor are sensitive to the small lattice distortion at the phase transition, and that an average of the total density of states, when all atoms participate in oscillations of all normal modes, are more similar to the experimental X-ray photoelectron spectra (XPS). The experimental splitting of CL obtained by XPS was compared with the theoretically calculated one by two different methods. The cluster model calculations showed that the splitting of the CL in SbSI might be caused by photoelectron emission from the atoms, which have different valence state, at the surface.

4

Effect of Vacancies on Electronic and Magnetic Properties of Hydrogen Passivated Graphene Nanoribbons

63%

Haffad S., Benchallal L., Lamiri L., Boubenider F., Zitoune H., Kahouadji B., Samah M.

Acta Physica Polonica A

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2018

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vol. 133

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issue 5

1307-1313

EN

Using first-principles calculations we have demonstrated that electronic and magnetic properties of armchair graphene nanoribbons are modified by introducing vacancies defects. The equilibrium geometries, electronic, charge spin density distributions, electronic band structures, and magnetic moments were examined in the presence of vacancies. We have found that introducing vacancies into armchair graphene nanoribbons changes the spatial distribution of neighbor atoms, particularly those located around the vacancies. Our calculations showed that the vacancies have significant effect on the magnetization of armchair graphene nanoribbons. Magnetic moment values and electronic behavior in different configurations depend on the number of vacancies. These results suggest that vacancy defects can be used to modify the electronic and the magnetic properties of armchair graphene nanoribbons.

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2 Open Physics

1 Acta Physica Polonica A

1 Archives of Acoustics

2 2018

1 2007

1 2005

1 Akkus H.

1 Audzijonis A.

1 Benchallal L.

1 Boubenider F.

1 Gaigalas G.

1 Haffad S.

1 Kahouadji B.

1 Lamiri L.

1 Mamedov A.

1 Narusis J.

1 Pauliukas A.

1 Qian D.

1 Samah M.

1 Zitoune H.

1 Čerškus A.

1 Žaltauskas R.

1 Žigas L.

Ab-initio calculation of band structure and linear optical properties of SbSI in para- and ferroelectric phases

Wave Propagation in a LRPC Composite Double Panel Structure with Periodically Attached Pillars and Etched Holes

Theoretical investigation of the electronic structure of a ferroelectric SbSI cluster at a phase transition

Effect of Vacancies on Electronic and Magnetic Properties of Hydrogen Passivated Graphene Nanoribbons