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Electronic structure and optical properties of noncentrosymmetric LiGaSe2 : Experimental measurements and DFT band structure calculations. / Lavrentyev, A. A.; Gabrelian, B. V.; Vu, V. T. и др.
в: Optical Materials, Том 66, 01.04.2017, стр. 149-159.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Electronic structure and optical properties of noncentrosymmetric LiGaSe2
T2 - Experimental measurements and DFT band structure calculations
AU - Lavrentyev, A. A.
AU - Gabrelian, B. V.
AU - Vu, V. T.
AU - Ananchenko, L. N.
AU - Isaenko, L. I.
AU - Yelisseyev, A. P.
AU - Khyzhun, O. Y.
PY - 2017/4/1
Y1 - 2017/4/1
N2 - We report on measurements of X-ray photoelectron (XP) spectra for pristine and Ar+ ion-irradiated surfaces of LiGaSe2 single crystal grown by Bridgman-Stockbarger method. Electronic structure of the LiGaSe2 compound is studied from a theoretical and experimental viewpoint. In particular, total and partial densities of states of LiGaSe2 are investigated by density functional theory (DFT) calculations employing the augmented plane wave + local orbitals (APW + lo) method and they are verified by data of X-ray spectroscopy measurements. The DFT calculations indicate that the main contributors to the valence band of LiGaSe2 are the Se 4p states, which contribute mainly at the top and in the upper portion of the valence band, with also essential contributions of these states in the lower portion of the band. Other substantial contributions to the valence band of LiGaSe2 emerge from the Ga 4s and Ga 4p states contributing mainly at the lower ant upper portions of the valence band, respectively. With respect to the conduction band, the calculations indicate that its bottom is composed mainly from contributions of the unoccupied Ga s and Se p states. The present calculations are confirmed experimentally when comparing the XP valence-band spectrum of the LiGaS2 single crystal on a common energy scale with the X-ray emission bands representing the energy distribution of the Ga 4p and Se 4p states. Measurements of the fundamental absorption edges at room temperature reveal that bandgap value, Eg, of LiGaSe2 is equal to 3.47 eV and the Eg value increases up to 3.66 eV when decreasing temperature to 80 K. The main optical characteristics of the LiGaSe2 compound are clarified by the DFT calculations.
AB - We report on measurements of X-ray photoelectron (XP) spectra for pristine and Ar+ ion-irradiated surfaces of LiGaSe2 single crystal grown by Bridgman-Stockbarger method. Electronic structure of the LiGaSe2 compound is studied from a theoretical and experimental viewpoint. In particular, total and partial densities of states of LiGaSe2 are investigated by density functional theory (DFT) calculations employing the augmented plane wave + local orbitals (APW + lo) method and they are verified by data of X-ray spectroscopy measurements. The DFT calculations indicate that the main contributors to the valence band of LiGaSe2 are the Se 4p states, which contribute mainly at the top and in the upper portion of the valence band, with also essential contributions of these states in the lower portion of the band. Other substantial contributions to the valence band of LiGaSe2 emerge from the Ga 4s and Ga 4p states contributing mainly at the lower ant upper portions of the valence band, respectively. With respect to the conduction band, the calculations indicate that its bottom is composed mainly from contributions of the unoccupied Ga s and Se p states. The present calculations are confirmed experimentally when comparing the XP valence-band spectrum of the LiGaS2 single crystal on a common energy scale with the X-ray emission bands representing the energy distribution of the Ga 4p and Se 4p states. Measurements of the fundamental absorption edges at room temperature reveal that bandgap value, Eg, of LiGaSe2 is equal to 3.47 eV and the Eg value increases up to 3.66 eV when decreasing temperature to 80 K. The main optical characteristics of the LiGaSe2 compound are clarified by the DFT calculations.
KW - Electronic structure
KW - Optical properties
KW - Semiconductors
KW - X-ray emission spectroscopy
KW - X-ray photoelectron spectroscopy
KW - TEMPERATURE-DEPENDENCE
KW - SUSCEPTIBILITIES
KW - MID-IR
KW - LIGAX2 X
KW - CHALCOGENIDES
KW - SINGLE-CRYSTAL
KW - SE
KW - RAY SPECTROSCOPY MEASUREMENTS
KW - 1ST-PRINCIPLES
KW - GROWTH
UR - http://www.scopus.com/inward/record.url?scp=85012050278&partnerID=8YFLogxK
U2 - 10.1016/j.optmat.2017.01.049
DO - 10.1016/j.optmat.2017.01.049
M3 - Article
AN - SCOPUS:85012050278
VL - 66
SP - 149
EP - 159
JO - Optical Materials
JF - Optical Materials
SN - 0925-3467
ER -
ID: 10036817