Lifshitz Transition and Band Structure Evolution in Alkali Metal Intercalated 1T′-MoTe2

Abstract

In van der Waals materials, coupling between adjacent layers is weak, and consequently interlayer interactions are weakly screened. This opens the possibility to profoundly modify the electronic structure, e.g., by applying electric fields or with adsorbates. Here, we show for the case of the topologically trivial semimetal 1T′-MoTe₂ that potassium dosing at room temperature significantly transforms its band structure. With a combination of angle-resolved photoemission spectroscopy, scanning tunneling microscopy, X-ray photoemission spectroscopy, and density functional theory we show that (i) for small concentrations of K, 1T′-MoTe₂ undergoes a Lifshitz transition with the electronic structure shifting rigidly, and (ii) for larger K concentrations 1T′-MoTe₂ undergoes significant band structure transformation. Our results demonstrate that the origin of this electronic structure change stems from alkali metal intercalation.