α−As2Te3 as a platform for the exploration of the electronic band structure of single layer β−tellurene

Arsenic telluride, ${\mathrm{As}}_{2}{\mathrm{Te}}_{3}$, is a layered van der Waals (vdW) semiconducting material usually known for its thermoelectric properties. It is composed of layers stacked together via weak vdW interactions, which can consequently be exfoliated into thin two-dimensional layers. Here, we studied the electronic properties of the $\ensuremath{\alpha}$ phase of ${\mathrm{As}}_{2}{\mathrm{Te}}_{3}$ by using angle-resolved photoemission spectroscopy (ARPES) and density-functional theory (DFT). In addition to the spectroscopic signature of $\ensuremath{\alpha}\ensuremath{-}{\mathrm{As}}_{2}{\mathrm{Te}}_{3}$, we were able to isolate anisotropic 2D electronic states, decoupled from the $\ensuremath{\alpha}\ensuremath{-}{\mathrm{As}}_{2}{\mathrm{Te}}_{3}$ electronic structure, that we propose to ascribe to single layer (SL) $\ensuremath{\beta}\ensuremath{-}\mathrm{tellurene}$. Our findings are supported by theoretical investigations using DFT, which reproduce the main ARPES experimental features. Our work thereby proposes $\ensuremath{\alpha}\ensuremath{-}{\mathrm{As}}_{2}{\mathrm{Te}}_{3}$ (100) surface as an interesting platform for the experimental exploration of the electronic band structure of SL $\ensuremath{\beta}\ensuremath{-}\mathrm{tellurene}$, which has been difficult to experimentally access otherwise.