{"title":"Antiferromagnetic Excitonic Insulator","authors":"V. V. Val’kov","doi":"10.1134/s1063776123100138","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The effective the two-band Hamiltonian is obtained for iridium oxides with account for strong electron correlations (SEC) and the spin–orbit interaction. The intraatomic electron correlations in iridium ions induce the formation of Hubbard fermions (HF) filling the states in the valence band. Another consequence of SEC is associated with the emergence of the antiferromagnetic (AFM) exchange interaction between HF in accordance with the Anderson mechanism. As a result, a long-range antiferromagnetic order is established in the system, and in the conditions of band overlapping, the intersite Coulomb interaction induces a phase transition to the excitonic insulator (EI) state with a long-range AFM order. The system of integral self-consistent equations, the solution to which determines the excitonic order parameter components Δ<sub><i>i</i>,</sub> <sub><i>j</i></sub>(<i>k</i>), sublattice magnetization <i>M</i>, Hubbard fermion concentration <i>n</i><sub><i>d</i></sub>, and chemical potential μ, is obtained using the atomic representation, the method of two-time temperature Green’s functions, and the Zwanzig–Mori projection technique. The symmetry classification of AFM EI phases is performed, and it is shown that in the nearest neighbor approximation, state Δ<sub><i>i</i>,</sub> <sub><i>j</i></sub>(<i>k</i>) with the <i>s</i>-type symmetry corresponds to the ground state, while the phases with the <i>d</i>- and <i>p</i>-symmetries are metastable.</p>","PeriodicalId":629,"journal":{"name":"Journal of Experimental and Theoretical Physics","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2023-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Experimental and Theoretical Physics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1134/s1063776123100138","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The effective the two-band Hamiltonian is obtained for iridium oxides with account for strong electron correlations (SEC) and the spin–orbit interaction. The intraatomic electron correlations in iridium ions induce the formation of Hubbard fermions (HF) filling the states in the valence band. Another consequence of SEC is associated with the emergence of the antiferromagnetic (AFM) exchange interaction between HF in accordance with the Anderson mechanism. As a result, a long-range antiferromagnetic order is established in the system, and in the conditions of band overlapping, the intersite Coulomb interaction induces a phase transition to the excitonic insulator (EI) state with a long-range AFM order. The system of integral self-consistent equations, the solution to which determines the excitonic order parameter components Δi,j(k), sublattice magnetization M, Hubbard fermion concentration nd, and chemical potential μ, is obtained using the atomic representation, the method of two-time temperature Green’s functions, and the Zwanzig–Mori projection technique. The symmetry classification of AFM EI phases is performed, and it is shown that in the nearest neighbor approximation, state Δi,j(k) with the s-type symmetry corresponds to the ground state, while the phases with the d- and p-symmetries are metastable.
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Journal of Experimental and Theoretical Physics is one of the most influential physics research journals. Originally based on Russia, this international journal now welcomes manuscripts from all countries in the English or Russian language. It publishes original papers on fundamental theoretical and experimental research in all fields of physics: from solids and liquids to elementary particles and astrophysics.
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