The Study for Two-dimensional PtX2 (X=S Se Te) Which Have Geometrical Structures Fully Composed of Pentagons.

Abstract

In this paper, we mainly use the first-principles method based on density functional theory to study the structure and electronic properties of three new two-dimensional materials consisting of five-membered rings, PtS2, PtSe2 and PtTe2. Based on the structure of the pentagon tile of Cairo, the substitution of Pt, S and Pt, Se and Pt, Te between the atoms in the unequal position of the minimum repeating unit will result in different structures, and then different structures will be obtained. The obtained structure is optimized, and the phonon spectrum is calculated. Finally, the three phonon spectrum stable structures of penta-PtS2, penta-PtSe2 and penta-PtTe2 are obtained. Then we proved the stability of these three structures from the aspects of dynamics and thermodynamics. Then their electronic properties were studied. From the calculated energy band diagram, we found that these three structures are indirect band gap semiconductors.