Charge doping into spin minority states mediates doubling of TC in ferromagnetic CrGeTe3
Abstract The recent discovery of the persistence of long-range magnetic order when van der Waals magnets are thinned towards monolayers provides a tunable platform for engineering of novel magnetic structures and devices. Here, we study the evolution of the electronic structure of CrGeTe 3 as a function of surface electron doping. From angle-resolved photoemission, we observe spectroscopic fingerprints that this electron doping drives a marked increase in T C , reaching values more than double that of the undoped material, in agreement with recent studies using electrostatic gating. Together with density functional theory calculations and Monte Carlo simulations, we show that, surprisingly, the increased T C is mediated by the population of spin-minority Cr t 2 g states, forming a half-metallic 2D electron gas. This promotes a novel variant of double exchange, and unlocks a significant influence of Ge – which was previously thought to be electronically inert in this system – in mediating Cr-Cr exchange.
Authors
- G. Balakrishnan (ORCID: https://orcid.org/0000-0002-5890-1149)
- Wei Ren (ORCID: https://orcid.org/0000-0001-7317-3867)
- Edgar Abarca Morales (ORCID: https://orcid.org/0000-0002-7714-8228)
- Igor Marković (ORCID: https://orcid.org/0000-0002-1631-9556)
- P. D. C. King (ORCID: https://orcid.org/0000-0002-6523-9034)
- Tommaso Antonelli (ORCID: https://orcid.org/0000-0002-4990-7813)
- Lei Qiao (ORCID: https://orcid.org/0000-0002-9277-3582)
- Monica Ciomaga Hatnean (ORCID: https://orcid.org/0000-0003-2870-8847)
- Matthew D. Watson (ORCID: https://orcid.org/0000-0002-0737-2814)
- Céphise Cacho (ORCID: https://orcid.org/0000-0002-0058-5817)
- Silvia Picozzi (ORCID: https://orcid.org/0000-0002-3232-788X)
- Liam Trzaska (ORCID: https://orcid.org/0009-0002-1556-3378)
Institutions
- Shanghai University (CN)
- University of St Andrews (GB)
- Diamond Light Source (GB)
- University of Warwick (GB)
- Max Planck Institute for Chemical Physics of Solids (DE)
Publication Details
- Journal
- npj 2D Materials and Applications
- Published
- 2025-01-16
- DOI
- https://doi.org/10.1038/s41699-025-00526-8
- Citations
- 2
- Primary Topic
- 2D Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 1.04
Funders
- Diamond Light Source
- Leverhulme Trust
- Royal Society
- National Natural Science Foundation of China
- Ministero dell’Istruzione, dell’Università e della Ricerca
- Science and Technology Commission of Shanghai Municipality
- China Scholarship Council
- International Max Planck Research School for Chemistry and Physics of Quantum Materials
- Ministero dell'Università e della Ricerca
- Engineering and Physical Sciences Research Council