Excitonic Insulator and the Extended Falicov--Kimball Model Away from Half-Filling
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866908736121995264 |
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| author | Golosov, D. I. |
| author_facet | Golosov, D. I. |
| contents | We consider an extended spinless Falicov--Kimball model at an arbitrary doping level, focusing on the range of parameter values where a uniform excitonic insulator is stabilised at half-filling. We compare the properties of possible uniform phases and construct the Hartree--Fock phase diagrams, which include sizeable phase separation regions. It is seen that the excitonic insulator can appear as a component phase in a mixed-phase state in a broad interval of doping levels. In addition, in a certain range of parameter values the excitonic metal (doped excitonic insulator) is identified as the lowest-energy uniform phase. We suggest that this phase, which is unstable with respect to phase separation, may be stabilised when the phase separation is suppressed by the long-range Coulomb interaction. Overall, we find that excitonic correlations can affect the behaviour of the system relatively far away from half-filling. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_13967 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Excitonic Insulator and the Extended Falicov--Kimball Model Away from Half-Filling Golosov, D. I. Strongly Correlated Electrons Materials Science We consider an extended spinless Falicov--Kimball model at an arbitrary doping level, focusing on the range of parameter values where a uniform excitonic insulator is stabilised at half-filling. We compare the properties of possible uniform phases and construct the Hartree--Fock phase diagrams, which include sizeable phase separation regions. It is seen that the excitonic insulator can appear as a component phase in a mixed-phase state in a broad interval of doping levels. In addition, in a certain range of parameter values the excitonic metal (doped excitonic insulator) is identified as the lowest-energy uniform phase. We suggest that this phase, which is unstable with respect to phase separation, may be stabilised when the phase separation is suppressed by the long-range Coulomb interaction. Overall, we find that excitonic correlations can affect the behaviour of the system relatively far away from half-filling. |
| title | Excitonic Insulator and the Extended Falicov--Kimball Model Away from Half-Filling |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2507.13967 |