Observation of charge density wave excitonic order parameter in topological insulator monolayer WTe2

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...

Descripción completa

Detalles Bibliográficos
Autores: Watson, Liam, Ripoll Sau, Joan, Tong, Zhengjue, Kumar, Amit, Que, Yande, Chan, Yang-Hao, Lin, Hsin, Mukherjee, Shantanu, Garnica Alonso, Manuela, Edmonds, MarkT., Papaj, Michal, López Vázquez de Parga, Amadeo, Weber, Bent, Di Bernardo, Iolanda, Fuhrer, Michael S.
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/733820
Acceso en línea:https://hdl.handle.net/10486/733820
https://dx.doi.org/10.1021/acsnano.5c08005
Access Level:acceso abierto
Palabra clave:excitonic order parameter
charge density wave
topological excitonic insulator
edge state
monolayer tungsten ditelluride (WTe2)
Física
Descripción
Sumario: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 of highly n- and p-doped WTe2. We observe additional nondispersive spatial modulations in the LDOS imprinted on the topological edge mode of neutral WTe2 on metallic substrates (graphene and graphite), which we interpret as the interaction of the topological edge mode with the expected charge density wave order parameter of the excitonic condensate in WTe2 at low interaction strength due to screening by the metallic substrates

Similares en LA Referencia