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TT: Fachverband Tiefe Temperaturen
TT 6: Focus Session Many-Body Phenomena in Nanomagnets: Kondo, Spinons, Spinarons and Beyond (joint session O/TT)
TT 6.2: Hauptvortrag
Montag, 17. März 2025, 15:30–16:00, H24
Electron delocalization in a 2D Mott insulator — •Amadeo L. Vazquez de Parga1,2,4,5, Cosme G. Ayani1,2, Michele Pisarra3, Iván M. Ibarburu1, Clara Rebanal1, Manuela Garnica2,4, Fabián Calleja2, and Fernando Martín1,2 — 1Universidad Autónoma de Madrid, Madrid, Spain — 2IMDEA Nanociencia, Madrid, Spain — 3Universitá della Calabria, Rende, Italy — 4Instituto Nicolás Cabrera, Madrid, Spain — 5Condensed Matter Physics Center (IFIMAC), Madrid, Spain
We follow by means of low temperature Scanning Tunneling Microscopy and Spectroscopy, the buildup of a 2D Kondo lattice in a system composed by a 2D Mott insulator, a single 1T-TaS2 layer, stacked on the surface of a metallic crystal, 2H-TaS2. When the sample temperature is lower than 27K, the magnetic moments present in the Mott insulator experience the Kondo screening by the conduction electrons of the metal, leading to the appearance of a Kondo resonance at the Fermi level. Below 11 K, a gap opens within the Kondo resonance, which is the signature of the formation of a coherent quantum state that extends all over the sample, i.e., a Kondo lattice [1]. Quasi particles interference maps reveal the emergence of a Fermi contour in the 2D Mott insulator when the temperature drops below 11K, indicating the delocalization of the highly correlated Mott electrons [2]. The observed modifications in the LDOS are well explained by state-of-the-art Density Functional Theory calculations.
[1] Small 20, 2303275 (2024) [2] Nat. Commun. 15, 10272 (2024)
Keywords: Highly correlated electrons; Kondo lattice; Transition metal dichalcogenides; van der Waals heterostructures; scanning tunneling microscopy/spectroscopy