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 (Δ<i>V</i>) 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 Δ<i>V</i> 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 Δ<i>V</i> and establishes a predictive framework for designing metal-TMDC contact barriers.