First-principles study of SiO 2 / MoS 2 and SiO 2 / WS 2 interfaces: A comparative analysis of surface terminations, van der Waals corrections, and functionals

Abstract

This study presents a first-principles investigation of SiO 2 / MoS 2 and SiO 2 / WS 2 interfaces, examining how surface terminations, van der Waals (vdW) corrections, and functional choices impact structural stability and electronic properties. Using density functional theory with generalized gradient approximation (GGA; PBE, PBEsol, revPBE), meta-GGA (SCAN, r 2 SCAN), and hybrid (PBE0) functionals, we assess the effect of vdW correction schemes (D2, D3, Tkatchenko-Scheffler) on interfacial energetics and separation. The results show that vdW corrections are essential for accurate GGA descriptions, while meta-GGAs yield similar accuracy even without them, enabling efficient modeling of SiO 2 /2D heterostructures. Additionally, SiO 2 surface morphology plays a significant role, with fully saturated interfaces showing lower energy and greater interlayer separations. In both SiO 2 / MoS 2 and SiO 2 / WS 2 systems, band gap predictions using PBE0 closely match the experimental values, underscoring the value of hybrid functionals for accurate electronic structure calculations.