Charge transfer and spin-valley locking in 4Hb-TaS2

Abstract 4Hb-TaS2 is a superconductor that exhibits unique characteristics such as time-reversal symmetry breaking, hidden magnetic memory, and topological edge modes. It is a naturally occurring heterostructure comprising of alternating layers of 1H-TaS2 and 1T-TaS2. The former is a well-known supe...

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Main Authors: Avior Almoalem, Roni Gofman, Yuval Nitzav, Ilay Mangel, Irena Feldman, Jahyun Koo, Federico Mazzola, Jun Fujii, Ivana Vobornik, J. S´anchez-Barriga, Oliver J. Clark, Nicholas Clark Plumb, Ming Shi, Binghai Yan, Amit Kanigel
Format: Article
Language:English
Published: Nature Portfolio 2024-04-01
Series:npj Quantum Materials
Online Access:https://doi.org/10.1038/s41535-024-00646-2
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Summary:Abstract 4Hb-TaS2 is a superconductor that exhibits unique characteristics such as time-reversal symmetry breaking, hidden magnetic memory, and topological edge modes. It is a naturally occurring heterostructure comprising of alternating layers of 1H-TaS2 and 1T-TaS2. The former is a well-known superconductor, while the latter is a correlated insulator with a possible non- trivial magnetic ground state. In this study, we use angle resolved photoemission spectroscopy to investigate the normal state electronic structure of this unconventional superconductor. Our findings reveal that the band structure of 4Hb-TaS2 fundamentally differs from that of its constituent materials. Specifically, we observe a significant charge transfer from the 1T layers to the 1H layers that drives the 1T layers away from half-filling. In addition, we find a substantial reduction in inter-layer coupling in 4Hb-TaS2 compared to the coupling in 2H-TaS2 that results in a pronounced spin-valley locking within 4Hb-TaS2.
ISSN:2397-4648