First-Principle Investigations on the Electronic and Transport Properties of PbBi(2)Te(2)X(2) (X = S/Se/Te) Monolayers

This paper reports first-principles calculations on PbBi [Formula: see text] Te [Formula: see text] S [Formula: see text] , PbBi [Formula: see text] Te [Formula: see text] Se [Formula: see text] and PbBi [Formula: see text] Te [Formula: see text] monolayers. The strain effects on their electronic and thermoelectric properties as well as on their stability have been investigated. Without strain, the PbBi [Formula: see text] Te [Formula: see text] monolayer exhibits highest Seebeck coefficient with a maximum value of 671 [Formula: see text] V/K. Under tensile strain the highest power factor are [Formula: see text] Wm [Formula: see text] K [Formula: see text] s [Formula: see text] , [Formula: see text] Wm [Formula: see text] K [Formula: see text] s [Formula: see text] and [Formula: see text] Wm [Formula: see text] K [Formula: see text] s [Formula: see text] for PbBi [Formula: see text] Te [Formula: see text] S [Formula: see text] , PbBi [Formula: see text] Te [Formula: see text] Se [Formula: see text] and PbBi [Formula: see text] Te [Formula: see text] at 3%, 2% and 1% tensile strains, respectively. These values are 85.9%, 55.0% and 3.3% larger than those of the unstrained structures.