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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2402.13238 |
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| _version_ | 1866929574927925248 |
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| author | Rossi, R. Simkovic IV, F. Ferrero, M. Georges, A. Tsvelik, A. M. Prokof'ev, N. V. Tupitsyn, I. S. |
| author_facet | Rossi, R. Simkovic IV, F. Ferrero, M. Georges, A. Tsvelik, A. M. Prokof'ev, N. V. Tupitsyn, I. S. |
| contents | The spin-fermion (SF) model postulates that the dominant coupling between low-energy fermions in near critical metals is mediated by collective spin fluctuations (paramagnons) peaked at the Néel wave vector, ${\bf Q}_N$, connecting hot spots on opposite sides of the Fermi surface. It has been argued that strong correlations at hot spots lead to a Fermi surface deformation (FSD) featuring flat regions and increased nesting. This conjecture was confirmed in the perturbative self-consistent calculations when the paramagnon propagator dependence on momentum deviation from ${\bf Q}_N$ is given by $χ^{-1} \propto |Δq|$. Using diagrammatic Monte Carlo (diagMC) technique we show that such a dependence holds only at temperatures orders of magnitude smaller than any other energy scale in the problem, indicating that a different mechanism may be at play. Instead, we find that a $χ^{-1} \propto |Δq|^{2}$ dependence yields a robust finite-$T$ scenario for achieving FSD. To link phenomenological and microscopic descriptions, we applied the connected determinant diagMC method to the $(t-t')$ Hubbard model and found that in this case: (i) the FSD is not very pronounced, and, instead, it is the lines of zeros of the renormalized dispersion relation that deform towards nesting; (ii) this phenomenon appears at large $U/t>5.5$ before the formation of electron and hole pockets; (iii) the static spin susceptibility is well described by $χ^{-1} \propto |Δq|^{2}$. Flat FS regions yield a non-trivial scenario for realizing a non-Fermi liquid state. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_13238 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Interaction-enhanced nesting in Spin-Fermion and Fermi-Hubbard models Rossi, R. Simkovic IV, F. Ferrero, M. Georges, A. Tsvelik, A. M. Prokof'ev, N. V. Tupitsyn, I. S. Strongly Correlated Electrons Superconductivity The spin-fermion (SF) model postulates that the dominant coupling between low-energy fermions in near critical metals is mediated by collective spin fluctuations (paramagnons) peaked at the Néel wave vector, ${\bf Q}_N$, connecting hot spots on opposite sides of the Fermi surface. It has been argued that strong correlations at hot spots lead to a Fermi surface deformation (FSD) featuring flat regions and increased nesting. This conjecture was confirmed in the perturbative self-consistent calculations when the paramagnon propagator dependence on momentum deviation from ${\bf Q}_N$ is given by $χ^{-1} \propto |Δq|$. Using diagrammatic Monte Carlo (diagMC) technique we show that such a dependence holds only at temperatures orders of magnitude smaller than any other energy scale in the problem, indicating that a different mechanism may be at play. Instead, we find that a $χ^{-1} \propto |Δq|^{2}$ dependence yields a robust finite-$T$ scenario for achieving FSD. To link phenomenological and microscopic descriptions, we applied the connected determinant diagMC method to the $(t-t')$ Hubbard model and found that in this case: (i) the FSD is not very pronounced, and, instead, it is the lines of zeros of the renormalized dispersion relation that deform towards nesting; (ii) this phenomenon appears at large $U/t>5.5$ before the formation of electron and hole pockets; (iii) the static spin susceptibility is well described by $χ^{-1} \propto |Δq|^{2}$. Flat FS regions yield a non-trivial scenario for realizing a non-Fermi liquid state. |
| title | Interaction-enhanced nesting in Spin-Fermion and Fermi-Hubbard models |
| topic | Strongly Correlated Electrons Superconductivity |
| url | https://arxiv.org/abs/2402.13238 |