Electronic structure and optical conductivity of two dimensional (2D) MoS2: Pseudopotential DFT versus full potential calculations

Abstract

We report first principle comparative study of electronic structure and optical conductivity of two dimensional (2D) MoS2 using pseudopotential based DFT and full potential calculations within generalized gradient approximation (GGA). We find direct band gap 1.83 eV and 1.79 eV respectively with pseudopotential and full potential calculations, which are in excellent agreement with recently measured direct band gap of 1.80 eV with optical spectroscopy. States around the Fermi energy are mainly derived from 4d orbitals of Mo. Calculated optical conductivity with pseudopotential finds very good agreements to full potential optical conductivity for E vector perpendicular to c axis and finds interband transitions mainly from p valance bands of S to the d conduction bands of Mo.