Single-Particle Dispersion and Density of States of the Half-Filled 2D Hubbard Model
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866911095591010304 |
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| author | Schumm, Gabe Zhang, Shiwei Sandvik, Anders W. |
| author_facet | Schumm, Gabe Zhang, Shiwei Sandvik, Anders W. |
| contents | Implementing an improved method for analytic continuation and working with imaginary-time correlation functions computed using quantum Monte Carlo simulations, we resolve the single-particle dispersion relation and the density of states (DOS) of the two-dimensional Hubbard model at half-filling. At intermediate interactions of $U/t = 4,6$, we find quadratic dispersion around the gap minimum at wave-vectors $\mathbf{k} = (\pm π/2, \pm π/2)$ (the $Σ$ points). We find saddle points at $\mathbf{k} = (\pm π,0),(0,\pm π)$ (the X points) where the dispersion is approximately quartic, leading to a sharp DOS maximum above the almost flat ledge arising from the states close to $Σ$. The fraction of quasiparticle states within the ledge is $n_{\rm ledge} \approx 0.15$. Upon doping away from half-filling, within the rigid-band approximation, these results support Fermi pockets around the $Σ$ points, with states around the X points becoming filled only at doping fractions $x \ge n_{\rm ledge}$. The high density of states away from the $Σ$ gap edge may be an important clue for a finite minimum doping level for superconductivity and other instabilities of doped Mott insulators. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_02614 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Single-Particle Dispersion and Density of States of the Half-Filled 2D Hubbard Model Schumm, Gabe Zhang, Shiwei Sandvik, Anders W. Strongly Correlated Electrons Implementing an improved method for analytic continuation and working with imaginary-time correlation functions computed using quantum Monte Carlo simulations, we resolve the single-particle dispersion relation and the density of states (DOS) of the two-dimensional Hubbard model at half-filling. At intermediate interactions of $U/t = 4,6$, we find quadratic dispersion around the gap minimum at wave-vectors $\mathbf{k} = (\pm π/2, \pm π/2)$ (the $Σ$ points). We find saddle points at $\mathbf{k} = (\pm π,0),(0,\pm π)$ (the X points) where the dispersion is approximately quartic, leading to a sharp DOS maximum above the almost flat ledge arising from the states close to $Σ$. The fraction of quasiparticle states within the ledge is $n_{\rm ledge} \approx 0.15$. Upon doping away from half-filling, within the rigid-band approximation, these results support Fermi pockets around the $Σ$ points, with states around the X points becoming filled only at doping fractions $x \ge n_{\rm ledge}$. The high density of states away from the $Σ$ gap edge may be an important clue for a finite minimum doping level for superconductivity and other instabilities of doped Mott insulators. |
| title | Single-Particle Dispersion and Density of States of the Half-Filled 2D Hubbard Model |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2504.02614 |