  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.
