Electron delocalization in a 2D Mott insulator

28.11.2024

Band-selective JDOS calculation overlaid on the experimental data on the 2H-TaS₂ . Credit: Amadeo L. Vázquez de Parga.

Madrid, 28th November, 2024. The prominent role of electron-electron interactions in two-dimensional (2D) materials versus three dimensional (3D) ones is at the origin of the great variety of fermionic correlated states reported in the literature. In this respect, artificial van der Waals heterostructures comprising single layers of highly correlated insulators allow one to explore the effect of the subtle interlayer interaction in the way electrons correlate. We study the temperature dependence of the electronic properties of a van der Waals heterostructure composed of a single-layer Mott insulator lying on a metallic substrate by performing quasi-particle interference (QPI) maps. We show the emergence of a Fermi contour in the 2D Mott insulator at temperatures below 11K, which we attribute to the delocalization of the Mott electrons associated with the formation of a quantum coherent Kondo lattice. This Kondo lattice introduces a new periodicity in the system, so that the resulting Fermi surface encompasses both the substrate conduction electrons and the now delocalized correlated electrons from the 2D Mott insulator. The comparison between experiments and Density Functional Theory calculations allows us to identify the signals observed in the quasi-particle interference maps. This provides a complete picture of the delocalization in the substrate conduction bands of the highly correlated electron from the 2D Mott insulator.

Reference:

Cosme G. Ayani, Michele Pisarra, Iván M. Ibarburu, Clara Rebanal, Manuela Garnica, Fabián Calleja, Fernando Martín, Amadeo L. Vázquez de Parga. Electron delocalization in a 2D Mott insulator. Nat Commun 15, 10272 (2024). https://doi.org/10.1038/s41467-024-54747-4

https://repositorio.imdeananociencia.org/handle/20.500.12614/3818

Contact:

Amadeo L. Vázquez de Parga
al.vazquezdeparga[at]imdea.org
Group webpage: https://nanociencia.imdea.org/nanoscale-imaging-of-2d-materials/group-home

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Fuente: Amadeo L. Vázquez de Parga.