Descriptor-Based Classification of Interfacial Electronic Coupling in Janus XP3-Based 2D Heterostructures

TL;DR

This study introduces a descriptor-based framework to analyze and predict interfacial electronic coupling in Janus XP3 heterostructures, aiding the design of functional 2D materials for electronics and catalysis.

Contribution

It develops a physically grounded, descriptor-based approach to classify and understand interfacial interactions in XP3 heterostructures, enabling targeted material engineering.

Findings

Heterobilayers are energetically favorable and stable.

Interlayer interactions cause significant band structure changes.

Optical activity and band alignment suggest potential applications.

Abstract

Understanding and controlling interfacial electronic coupling in two-dimensional (2D) heterostructures is essential for designing functional materials for electronic, optoelectronic, and catalytic applications. Here, we investigate vertical heterobilayers constructed from two distinct XP3 monolayers (X = As, Ge, Sb, Bi, Sn, Al, Ga, and Pb) using first-principles density functional theory. The resulting Janus heterobilayers are energetically favorable and elastically stable, with electronic band gaps ranging from metallic and near-metallic to semiconducting regimes. Interlayer interactions induce significant band renormalization, including transitions between type I and type II alignment upon structural relaxation. To rationalize these effects, we establish a descriptor-based framework based on the metal metal interlayer distance, interfacial electron localization, and Bader charge redistribution. This combined analysis discriminates vdW-like, polar covalent, and ionic interaction regimes, with systematic trends governed by the average atomic number of the constituent elements. Optical absorption calculations indicate visible-to-near-infrared activity in selected systems, and band-edge alignment identifies promising candidates for selective redox processes. Overall, the proposed descriptor-based strategy provides a physically grounded route for identifying and engineering interfacial coupling in XP3 heterostructures and can be extended to other classes of two-dimensional material interfaces.