{"title":"掺杂哈伯德模型的动态 t/U 扩展","authors":"Wenxin Ding, Rong Yu","doi":"10.1088/0256-307x/41/3/037101","DOIUrl":null,"url":null,"abstract":"We construct a new <italic toggle=\"yes\">U</italic>(1) slave-spin representation for the single-band Hubbard model in the large-<italic toggle=\"yes\">U</italic> limit. The mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics of the Mott insulator at half-filling and the strange metal behavior at finite doping. By employing a dynamical Green’s function theory for slave spins, we calculate the single-particle spectral function of electrons. The result is comparable to that in dynamical mean field theories. We then formulate a dynamical <italic toggle=\"yes\">t</italic>/<italic toggle=\"yes\">U</italic> expansion for the doped Hubbard model that reproduces the mean-field results at the lowest order of expansion. To the next order of expansion, it naturally yields an effective low-energy theory of a <italic toggle=\"yes\">t</italic>–<italic toggle=\"yes\">J</italic> model for spinons self-consistently coupled to an <italic toggle=\"yes\">XXZ</italic> model for the slave spins. We show that the superexchange <italic toggle=\"yes\">J</italic> is renormalized by doping, in agreement with the Gutzwiller approximation. Surprisingly, we find a new <italic toggle=\"yes\">ferromagnetic</italic> channel of exchange interactions which survives in the infinite <italic toggle=\"yes\">U</italic> limit, as a manifestation of the Nagaoka ferromagnetism.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":"45 1","pages":""},"PeriodicalIF":3.5000,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Dynamical t/U Expansion of the Doped Hubbard Model\",\"authors\":\"Wenxin Ding, Rong Yu\",\"doi\":\"10.1088/0256-307x/41/3/037101\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"We construct a new <italic toggle=\\\"yes\\\">U</italic>(1) slave-spin representation for the single-band Hubbard model in the large-<italic toggle=\\\"yes\\\">U</italic> limit. The mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics of the Mott insulator at half-filling and the strange metal behavior at finite doping. By employing a dynamical Green’s function theory for slave spins, we calculate the single-particle spectral function of electrons. The result is comparable to that in dynamical mean field theories. We then formulate a dynamical <italic toggle=\\\"yes\\\">t</italic>/<italic toggle=\\\"yes\\\">U</italic> expansion for the doped Hubbard model that reproduces the mean-field results at the lowest order of expansion. To the next order of expansion, it naturally yields an effective low-energy theory of a <italic toggle=\\\"yes\\\">t</italic>–<italic toggle=\\\"yes\\\">J</italic> model for spinons self-consistently coupled to an <italic toggle=\\\"yes\\\">XXZ</italic> model for the slave spins. We show that the superexchange <italic toggle=\\\"yes\\\">J</italic> is renormalized by doping, in agreement with the Gutzwiller approximation. Surprisingly, we find a new <italic toggle=\\\"yes\\\">ferromagnetic</italic> channel of exchange interactions which survives in the infinite <italic toggle=\\\"yes\\\">U</italic> limit, as a manifestation of the Nagaoka ferromagnetism.\",\"PeriodicalId\":10344,\"journal\":{\"name\":\"Chinese Physics Letters\",\"volume\":\"45 1\",\"pages\":\"\"},\"PeriodicalIF\":3.5000,\"publicationDate\":\"2024-03-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Chinese Physics Letters\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1088/0256-307x/41/3/037101\",\"RegionNum\":2,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chinese Physics Letters","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1088/0256-307x/41/3/037101","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
Dynamical t/U Expansion of the Doped Hubbard Model
We construct a new U(1) slave-spin representation for the single-band Hubbard model in the large-U limit. The mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics of the Mott insulator at half-filling and the strange metal behavior at finite doping. By employing a dynamical Green’s function theory for slave spins, we calculate the single-particle spectral function of electrons. The result is comparable to that in dynamical mean field theories. We then formulate a dynamical t/U expansion for the doped Hubbard model that reproduces the mean-field results at the lowest order of expansion. To the next order of expansion, it naturally yields an effective low-energy theory of a t–J model for spinons self-consistently coupled to an XXZ model for the slave spins. We show that the superexchange J is renormalized by doping, in agreement with the Gutzwiller approximation. Surprisingly, we find a new ferromagnetic channel of exchange interactions which survives in the infinite U limit, as a manifestation of the Nagaoka ferromagnetism.
期刊介绍:
Chinese Physics Letters provides rapid publication of short reports and important research in all fields of physics and is published by the Chinese Physical Society and hosted online by IOP Publishing.