Polaronic mechanism of Nagaoka ferromagnetism in Hubbard models
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arXiv
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| Autores principales: | , |
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| Formato: | Preprint |
| Publicado: |
2023
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| _version_ | 1866916491320885248 |
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| author | Samajdar, Rhine Bhatt, R. N. |
| author_facet | Samajdar, Rhine Bhatt, R. N. |
| contents | The search for elusive Nagaoka-type ferromagnetism in the Hubbard model has recently enjoyed renewed attention with the advent of a variety of experimental platforms enabling its realization, including moiré materials, quantum dots, and ultracold atoms in optical lattices. Here, we demonstrate a universal mechanism for Nagaoka ferromagnetism (that applies to both bipartite and nonbipartite lattices) based on the formation of ferromagnetic polarons consisting of a dopant dressed with polarized spins. Using large-scale density-matrix renormalization group calculations, we present a comprehensive study of the ferromagnetic polaron in an electron-doped Hubbard model, establishing various polaronic properties such as its size and energetics. Moreover, we systematically probe the internal structure of the magnetic state$\unicode{x2014}$through the use of pinning fields and three-point spin-charge-spin correlation functions$\unicode{x2014}$for both the single-polaron limit and the high-density regime of interacting polarons. Our results highlight the crucial role of mobile polarons in the birth of global ferromagnetic order from local ferromagnetism and provide a unified framework to understand the development and demise of the Nagaoka-type ferromagnetic state across dopings. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2311_09279 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Polaronic mechanism of Nagaoka ferromagnetism in Hubbard models Samajdar, Rhine Bhatt, R. N. Strongly Correlated Electrons Quantum Gases Quantum Physics The search for elusive Nagaoka-type ferromagnetism in the Hubbard model has recently enjoyed renewed attention with the advent of a variety of experimental platforms enabling its realization, including moiré materials, quantum dots, and ultracold atoms in optical lattices. Here, we demonstrate a universal mechanism for Nagaoka ferromagnetism (that applies to both bipartite and nonbipartite lattices) based on the formation of ferromagnetic polarons consisting of a dopant dressed with polarized spins. Using large-scale density-matrix renormalization group calculations, we present a comprehensive study of the ferromagnetic polaron in an electron-doped Hubbard model, establishing various polaronic properties such as its size and energetics. Moreover, we systematically probe the internal structure of the magnetic state$\unicode{x2014}$through the use of pinning fields and three-point spin-charge-spin correlation functions$\unicode{x2014}$for both the single-polaron limit and the high-density regime of interacting polarons. Our results highlight the crucial role of mobile polarons in the birth of global ferromagnetic order from local ferromagnetism and provide a unified framework to understand the development and demise of the Nagaoka-type ferromagnetic state across dopings. |
| title | Polaronic mechanism of Nagaoka ferromagnetism in Hubbard models |
| topic | Strongly Correlated Electrons Quantum Gases Quantum Physics |
| url | https://arxiv.org/abs/2311.09279 |