Charge doping into spin minority states mediates doubling of T C 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 CrGeTe3 as a funct...
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2025-01-01
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| Series: | npj 2D Materials and Applications |
| Online Access: | https://doi.org/10.1038/s41699-025-00526-8 |
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| _version_ | 1832594730734583808 |
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| author | Liam Trzaska Lei Qiao Matthew D. Watson Monica Ciomaga Hatnean Igor Marković Edgar Abarca Morales Tommaso Antonelli Cephise Cacho Geetha Balakrishnan Wei Ren Silvia Picozzi Phil D. C. King |
| author_facet | Liam Trzaska Lei Qiao Matthew D. Watson Monica Ciomaga Hatnean Igor Marković Edgar Abarca Morales Tommaso Antonelli Cephise Cacho Geetha Balakrishnan Wei Ren Silvia Picozzi Phil D. C. King |
| author_sort | Liam Trzaska |
| collection | DOAJ |
| description | 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 CrGeTe3 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 2g 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. |
| format | Article |
| id | doaj-art-f14518c561e44f4fbba41cadf64869c4 |
| institution | Kabale University |
| issn | 2397-7132 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj 2D Materials and Applications |
| spelling | doaj-art-f14518c561e44f4fbba41cadf64869c42025-01-19T12:25:39ZengNature Portfolionpj 2D Materials and Applications2397-71322025-01-01911710.1038/s41699-025-00526-8Charge doping into spin minority states mediates doubling of T C in ferromagnetic CrGeTe3Liam Trzaska0Lei Qiao1Matthew D. Watson2Monica Ciomaga Hatnean3Igor Marković4Edgar Abarca Morales5Tommaso Antonelli6Cephise Cacho7Geetha Balakrishnan8Wei Ren9Silvia Picozzi10Phil D. C. King11SUPA, School of Physics and Astronomy, University of St AndrewsPhysics Department, International Center of Quantum and Molecular Structures, Materials Genome Institute, State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of High Temperature Superconductors, Shanghai UniversityDiamond Light Source, Harwell Science and Innovation CampusDepartment of Physics, University of WarwickSUPA, School of Physics and Astronomy, University of St AndrewsSUPA, School of Physics and Astronomy, University of St AndrewsSUPA, School of Physics and Astronomy, University of St AndrewsDiamond Light Source, Harwell Science and Innovation CampusDepartment of Physics, University of WarwickPhysics Department, International Center of Quantum and Molecular Structures, Materials Genome Institute, State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of High Temperature Superconductors, Shanghai UniversityConsiglio Nazionale delle Ricerche (CNR-SPIN), Unità di Ricerca presso Terzi c/o Università “G. D’Annunzio”SUPA, School of Physics and Astronomy, University of St AndrewsAbstract 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 CrGeTe3 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 2g 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.https://doi.org/10.1038/s41699-025-00526-8 |
| spellingShingle | Liam Trzaska Lei Qiao Matthew D. Watson Monica Ciomaga Hatnean Igor Marković Edgar Abarca Morales Tommaso Antonelli Cephise Cacho Geetha Balakrishnan Wei Ren Silvia Picozzi Phil D. C. King Charge doping into spin minority states mediates doubling of T C in ferromagnetic CrGeTe3 npj 2D Materials and Applications |
| title | Charge doping into spin minority states mediates doubling of T C in ferromagnetic CrGeTe3 |
| title_full | Charge doping into spin minority states mediates doubling of T C in ferromagnetic CrGeTe3 |
| title_fullStr | Charge doping into spin minority states mediates doubling of T C in ferromagnetic CrGeTe3 |
| title_full_unstemmed | Charge doping into spin minority states mediates doubling of T C in ferromagnetic CrGeTe3 |
| title_short | Charge doping into spin minority states mediates doubling of T C in ferromagnetic CrGeTe3 |
| title_sort | charge doping into spin minority states mediates doubling of t c in ferromagnetic crgete3 |
| url | https://doi.org/10.1038/s41699-025-00526-8 |
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