First-principles study of adatom-modified semiconductor monolayers as potential quantum simulators

Quantum simulators utilize quantum effects to study complex systems challenging for conventional methods. Semiconductor monolayers, particularly when modified with adatoms (adsorbed atoms), offer a promising platform for exploring artificial atoms in 2D (two-dimensional) materials for pursuing quantum phenomena. We investigated silver (Ag), gold (Au), and cesium (Cs) adsorbed on monolayers of gallium antimonide (GaSb), indium arsenide (InAs), and indium antimonide (InSb) as potential quantum simulators using density functional theory (DFT). Our calculations reveal that the Cs adatoms adsorbed on GaSb, InAs, and InSb monolayers demonstrate the most stable chemisorption among the nine analyzed systems. In contrast, other systems with Au or Ag adatoms exhibit weaker physisorption. Out of the systems with chemisorption and indirect bandgaps, Cs on InSb has the largest bandgap, followed by Cs on InAs. Larger bandgaps are more suitable for adatom manipulation on scanning tunneling microscopy/spectroscopy (STM/STS). These findings highlight the potential of Cs on either GaSb, InAs, or InSb for applications in adatoms on monolayers and provide valuable information for STM/STS experimentalists. Finally, we conclude that Cs on InSb is the most suitable one for creating stable artificial atoms on monolayers and quantum simulators.