Hybrid and resonant states originated by the stabilization of borophene’s single χ₆ polymorph on Ir(111)

Borophene, a single-atom-thick boron sheet, exhibits rich polymorphism that could enable control of its physical properties, though growing pre-designed polymorphs remains challenging due to complex interaction with metal substrates. Here, we investigate in detail the complex interfacial interactions between a layer of a single χ₆ borophene polymorph and the Ir(111) surface through a combined experimental and computational approach using scanning tunnelling microscopy/spectroscopy (STM/STS) and density functional theory (DFT). The emergence of a hybrid interface state (IFS) and novel hybrid and resonant image potential states (IPSs), which are anisotropically modulated along the borophene unit cell, is revealed. These findings provide comprehensive insight into the electronic properties of an intriguing borophene—substrate interface and deepen the understanding of interfacial physical phenomena occurring in substrate-supported two-dimensional (2D) materials.