Emerging Low-dimensional Ag and Cu Group-11 Monochalcogenides: Growth, Structures, and Physical Properties

Abstract

Transition-metal monochalcogenides (TMMs) have recently emerged as a distinctive branch of low-dimensional materials, offering structural motifs and electronic states that differ markedly from those of conventional layered chalcogenides. Their predominantly nonlayered bulk counterparts, however, make the stabilization of atomically thin phases highly dependent on bottom-up synthesis and substrate engineering. This review summarizes recent progress in Ag and Cu Group-11 Monochalcogenides, with particular emphasis on their growth, atomic structures, and physical properties. For Ag-based systems, the epitaxial realization of honeycomb AgTe and AgSe monolayers has established experimentally accessible platforms for investigating semiconducting behavior, spin-orbit-related effects, and symmetry-protected topological states. Cu-based systems display an even broader structural landscape, spanning two-dimensional CuSe monolayers with strain-sensitive electronic structures and nodal-line characteristics to quasi-one-dimensional CuTe chains exhibiting flat-band states and pronounced correlation effects. In parallel, first-principles studies continue to expand the family of potentially stable Ag- and Cu-based monochalcogenide phases and reveal substantial diversity in their electronic characteristics. Taken together, these advances demonstrate that lattice geometry, substrate coupling, and dimensionality are key parameters governing the properties of this material family. Continued progress in controlled synthesis, structural regulation, and electronic-state engineering is expected to further establish Ag- and Cu-based transition-metal monochalcogenides as versatile platforms for low-dimensional quantum materials and future functional devices.