Hundness in twisted bilayer graphene: correlated gaps and pairing
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arXiv
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| Main Authors: | , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866913596908240896 |
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| author | Youn, Seongyeon Goh, Beomjoon Zhou, Geng-Dong Song, Zhi-Da Lee, Seung-Sup B. |
| author_facet | Youn, Seongyeon Goh, Beomjoon Zhou, Geng-Dong Song, Zhi-Da Lee, Seung-Sup B. |
| contents | We characterize gap-opening mechanisms in the topological heavy fermion (THF) model of magic-angle twisted bilayer graphene (MATBG), with and without electron-phonon coupling, using dynamical mean-field theory (DMFT) with the numerical renormalization group (NRG) impurity solver. In the presence of symmetry breaking associated with valley-orbital ordering (time-reversal-symmetric or Kramers intervalley coherent, or valley polarized), spin anti-Hund and orbital-angular-momentum Hund couplings, induced by the dynamical Jahn-Teller effect, result in a robust pseudogap at filling $2 \lesssim |ν| \lesssim 2.5$. We also find that Hundness enhances the pairing susceptibilities for $1.6 \lesssim |ν| \lesssim 2.8$, which might be a precursor to the superconducting phases neighboring $|ν| = 2$. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_03108 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Hundness in twisted bilayer graphene: correlated gaps and pairing Youn, Seongyeon Goh, Beomjoon Zhou, Geng-Dong Song, Zhi-Da Lee, Seung-Sup B. Strongly Correlated Electrons Mesoscale and Nanoscale Physics We characterize gap-opening mechanisms in the topological heavy fermion (THF) model of magic-angle twisted bilayer graphene (MATBG), with and without electron-phonon coupling, using dynamical mean-field theory (DMFT) with the numerical renormalization group (NRG) impurity solver. In the presence of symmetry breaking associated with valley-orbital ordering (time-reversal-symmetric or Kramers intervalley coherent, or valley polarized), spin anti-Hund and orbital-angular-momentum Hund couplings, induced by the dynamical Jahn-Teller effect, result in a robust pseudogap at filling $2 \lesssim |ν| \lesssim 2.5$. We also find that Hundness enhances the pairing susceptibilities for $1.6 \lesssim |ν| \lesssim 2.8$, which might be a precursor to the superconducting phases neighboring $|ν| = 2$. |
| title | Hundness in twisted bilayer graphene: correlated gaps and pairing |
| topic | Strongly Correlated Electrons Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2412.03108 |