Analysis of Optical Properties of MoS2 Monolayer using Minimal-Basis Tight-Binding Models
N. Nouria,b, P. Potasz b, S. Zia Borujeni c, A. Wójs b and G. Rashedi a
aDepartment of Physics, Faculty of Sciences, University of Isfahan, Isfahan 81746-73441, Iran
bDepartment of Theoretical Physics, Wrocław University of Science and Technology, Wrocław, Poland
cDepartment of Mathematics, Faculty of Sciences, Tehran Central Branch, Islamic Azad University, Tehran, Iran
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Optical properties of transition metal dichalcogenides monolayer of MoS2 are analyzed using multi-orbital tight-binding models with only Mo d-orbitals (three-band model) and with an inclusion of S p-orbitals (six-band model). We look at band structures, momentum matrix elements between valence and conduction band, and joint optical density of states. Good agreement between the two models is shown in a vicinity of K point of the Brillouin zone. On line connecting K and Γp points, a local conduction band minimum at Q point is recovered only by six-band model in agreement with density functional theory and experimental results. We show that optical transitions at this point are active for both light polarizations. A peak in joint optical density of states is also seen at this point suggesting its potentially important role in a proper description of excitonic effects.

DOI: 10.12693/APhysPolA.132.313
PACS numbers: 73.20.At, 78.67.-n, 78.20.Bh