Importance of Many-Body Dispersion in the Stability of Vacancies and Antisites in Free-Standing Monolayer of MoS2 from First-Principles Approaches

Abstract

Defects in MoS2 monolayer play a vital role in altering the electric and optical properties, which is a crucial factor in various semiconducting and optoelectronic devices. In the present work, we have investigated the thermodynamic stability of point defects in MoS2 monolayer by means of first-principles based density functional theory (DFT) and ab initio atomistic thermodynamics. We have considered three vacancies and five antisites in our system, viz. Mo vacancy (VMo ), SMo antisite, S2Mo antisite, S vacancy (VS ), MoS antisite, S2 vacancy (VS2 ), MoS2 antisite and 2MoS2 antisite. Our approach includes (i) the two-body van der Waals (vdW) interaction under Tkatchenko-Scheffler (TS) scheme and (ii) many-body dispersion (MBD) to account the effect of polarization on the defects’ stability. The MBD effect has posed a significant change in the pattern of stable defects. Hence, we report the stable defect states as observed by hybrid DFT with MBD as, V−2S , V−2Mo and S−2Mo in n-type MoS 2 monolayer, and V+2...