Atomic-Scale Origins and Shielding-Corrected Dipole Predictions of Surface Electrostatic Potential Difference in Metal–TMDC Contacts

The atomic-scale origins and quantitative description of the surface electrostatic potential difference (ΔV) in metal–semiconductor contacts remain elusive, limiting rational interface barrier design. Through first-principles calculations on Au/Ag/Pt/Pd-transition-metal dichalcogenide (TMDC) contacts, we establish a robust linear correlation between ΔV and shielding-corrected dipole terms parametrized by atomic number (Z), valence electron count, and atomic radii. Three critical insights are identified. First, the dipole terms from metal–TMDC and TMDC–TMDC interfaces as well as TMDC layers dominate linearity with a contribution of about 90%–92%. Second, the interfaces and TMDC layers in closer proximity to the metal layer show reduced contributions due to suppression by the metallic free-electron region. Third, incorporating high-Z atomic shielding corrections collectively enhances linearity by 8%–10%, with a maximal correction from metal–TMDC interfaces. Using this correlation, interface barriers are predicted, matching those from band structures. This work clarifies the atomic origins of ΔV and establishes a predictive framework for designing metal–TMDC contact barriers.