Year: 2026
Type: article
Abstract: Transition metal ditellurides exhibit structural and electronic properties distinct from their selenide and sulfide counterparts, including the stabilization of multiple charge density wave (CDW) phases. Within the niobium compound family, notable differences in structure are also observed: bulk NbTe2 crystallizes in the 1T phase, distinguishing it from NbSe2 and NbS2, which typically adopt both the 2H and 1T structures. However, in this work, we report the unexpectedly successful synthesis of two-dimensional (2D) islands of the metastable 1H-NbTe2 phase via molecular beam epitaxy on epitaxial graphene supported on Ir(111). The phase is identified by its characteristic hexagonal lattice in combination with distinct spectroscopic features and the presence of mirror twin boundaries. A comprehensive analysis combining scanning tunneling spectroscopy (STS), angle-resolved photoemission spectroscopy (ARPES), and density functional theory (DFT) calculations confirms the metallic character and structural stability of the 1H-NbTe2 phase. Furthermore, low-temperature STS measurements reveal the formation of a 4 × 4 CDW modulation, which is explained based on a phonon instability. These findings motivate the exploration of the complex phase behavior and electronic properties of NbTe2 in the 2D limit.
Source: ACS Nano
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: Comunidad de Madrid, Ministerio de Ciencia, Innovación y Universidades, Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya, Universidad Autónoma de Madrid, Ministerio de Ciencia e Innovación, Barcelona Supercomputing Center, Dirección General de Universidades e Investigación, FP7 Coordination of Research Activities
Awards: G1050946522, G1146355530, G16903939, G2126327880, G2555171554, G2920075017, G3109769530, G3315615419, G3493280505, G3786434780, G4418367529, G4667094761, G4717959651, G5739649973, G5804979208, G594724612, G6653880895, G712589879, G9000385933, G9000848138, G9000848305, G9000848366, G9000848481, G9000848561, G9000849340
OpenAlex ID: W7216472304