First-principles study on electronic structure and thermodynamic stability of two-dimensional pentagonal MX2 (M = Pd, Pt; X = S, Se, Te)

In this work, we calculate the band gap and mobility of the two-dimensional (2D) pentagonal MX2 by means of first-principles method. Heyd Scuseria Ernzerhof (HSE06) hybrid functional calculation shows that the 2D pentagonal MX2 is an indirect bandgap semiconductor, and the band gap ranged from 1.86 eV to 3.01 eV. The effective mass and carrier mobility of the 2D pentagonal MX2 are studied and show anisotropic characteristics, the hole mobility of PtS2 is the highest (5009.42 cm2 V-1 s-1). According to these results, we find that the 2D pentagonal MX2 satisfied dynamic, chemical, and thermodynamic stability. All of these indicate the great application prospect of the 2D pentagonal MX2 semiconductor in electronic devices.