Manifestation of Anomalous Weak Space-Charge-Density Acentricity for a Tl4HgBr6Single Crystal.
Density functional theory (DFT) calculations within the concept of the MBJ+U+SO (modified Becke-Johnson potential + U + spin orbit) approach were performed for a Tl4HgBr6single crystal for the first time assuming weak noncentrosymmetry (space group P4nc). Excellent agreement was achieved between the calculated and experimental band-gap-energy magnitudes as well as the density of electronic states measured by the X-ray photoelectron spectroscopy method. It is a very principal result because usually the DFT calculations underestimate the energy-gap values. In the present study, we carry out calculations of the optical properties (absorption coefficient, real and imaginary parts of the dielectric function, electron energy-loss spectrum, refractive index, extinction coefficient, and optical reflectivity dispersions). It has been established that the principal origin of the observed weak acentricity is determined by delocalized band states at the top of the valence band originating from the p states of the Br atoms.
Department of Electrical Engineering and Electronics, Don State Technical University , Gagarin Sq. 1, 344010 Rostov-on-Don, Russian Federation.
Anatoliy A
AA
Lavrentyev
Department of Electrical Engineering and Electronics, Don State Technical University , Gagarin Sq. 1, 344010 Rostov-on-Don, Russian Federation.
Boris V
BV
Gabrelian
Department of Electrical Engineering and Electronics, Don State Technical University , Gagarin Sq. 1, 344010 Rostov-on-Don, Russian Federation.
Tuan V
TV
Vu
Department of Electrical Engineering and Electronics, Don State Technical University , Gagarin Sq. 1, 344010 Rostov-on-Don, Russian Federation.
Peter N
PN
Shkumat
Yuriy Fedkovych Chernivtsi National University , 2 Kotziubynskoho Street, UA-58012 Chernivtsi, Ukraine.
Petro M
PM
Fochuk
Department of Solid State Physics, Lesya Ukrainka Eastern European National University , 13 Voli Avenue, UA-4025 Lutsk, Ukraine.
Oleg V
OV
Parasyuk
Faculty of Electrical Engineering, Częstochowa University of Technology , Armii Krajowej 17, PL-42-217 Częstochowa, Poland.
Iwan V
IV
Kityk
Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine , 3 Krzhyzhanivsky Street, UA-03142 Kyiv, Ukraine.
Ivan V
IV
Luzhnyi
Frantsevych Institute for Problems of Materials Science, National Academy of Sciences of Ukraine , 3 Krzhyzhanivsky Street, UA-03142 Kyiv, Ukraine.
Oleg Y
OY
Khyzhun
Institute of Physics, J. Dlugosz University of Częstochowa , Armii Krajowej 13/15, PL-42-200 Częstochowa, Poland.
Michal
M
Piasecki