Observation of the Charge Density Wave Excitonic Order Parameter in Topological Insulator Monolayer WTe₂.

ABSTRACT: Strong electron-hole interactions in a semimetal or narrow-gap semiconductor may drive a ground state of condensed excitons. Monolayer WTe₂ has been proposed as a host material for such an exciton condensate, but the order parameter─the key signature of a macroscopic quantum-coherent condensate─has not been observed. Here, we use Fourier-transform scanning tunneling spectroscopy (FT-STS) to study quasiparticle interference (QPI) and periodic modulations of the local density of states (LDOS) in monolayer WTe₂. In WTe₂ on graphene, in which the carrier density can be varied via back-gating, FT-STS shows QPI features in the two-dimensional (2D) bulk bands, confirming the interacting nature of the bandgap in neutral WTe₂ and the semimetallic nature o

SUBMITTER: Watson L 

PROVIDER: S-EPMC12445006 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature