부산대학교 도서관

MoTe2 is a paradigmatic van der Waals layered semimetal with two energetically close electronic phases, the topologically trivial 1Tprime and the low-temperature Td type-II Weyl semimetal phase. The ability to manipulate this phase transition, perhaps towards occurring near room temperature, would open new avenues for harnessing the full potential of Weyl semimetals for high-efficiency electronic and spintronic applications. Here, we show that potassium dosing on 1Tprime-MoTe2 induces a Lifshitz transition by a combination of angle-resolved photoemission spectroscopy, scanning tunneling microscopy, x-ray spectroscopy and density functional theory. While the electronic structure shifts rigidly for small concentrations of K, MoTe2 undergoes significant band structure renormalization for larger concentrations. Our results demonstrate that the origin of this electronic structure change stems from alkali metal intercalation. We show that these profound changes are caused by effectively decoupling the 2D sheets, bringing K-intercalated 1Tprime-MoTe2 to the quasi-2D limit, but do not cause a topological phase transition.