Dirac points and topological phases in correlated altermagnets
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866909626310590464 |
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| author | Del Re, Lorenzo |
| author_facet | Del Re, Lorenzo |
| contents | We explore a two-dimensional Hubbard model adapted to host altermagnetic states. Utilizing Hartree-Fock (HF) and dynamical mean field theory (DMFT), we uncover that the magnetic solutions of this model feature Dirac points in their spectrum. HF predicts a gap opening at a critical interaction strength, a result corroborated by DMFT calculations at zero temperature. However, at finite temperature and high interaction strengths, Dirac points re-emerge at high energies in the spectral function, even if they are absent in the non-interacting and HF-predicted band structures. Analytical arguments reveal that this phenomenon arises near Mott insulating solutions from the frequency dependence of the self-energy, a behavior not captured by static mean-field theory. We identify distinctive dynamical signatures of correlated altermagnetic states in the spin-resolved optical conductivity, notably a double-peak structure likely linked to high-energy Dirac cone-like bands. Moreover, the spin-resolved response exhibits spin-selective activation at different photon energies, pointing to potential applications in spin-dependent optical control. We also propose perturbations to the model that can induce a topological gap in the spectrum, leading to a transition from topologically trivial to non-trivial states by varying doping, interaction strength, and temperature. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2408_14288 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Dirac points and topological phases in correlated altermagnets Del Re, Lorenzo Strongly Correlated Electrons Quantum Gases We explore a two-dimensional Hubbard model adapted to host altermagnetic states. Utilizing Hartree-Fock (HF) and dynamical mean field theory (DMFT), we uncover that the magnetic solutions of this model feature Dirac points in their spectrum. HF predicts a gap opening at a critical interaction strength, a result corroborated by DMFT calculations at zero temperature. However, at finite temperature and high interaction strengths, Dirac points re-emerge at high energies in the spectral function, even if they are absent in the non-interacting and HF-predicted band structures. Analytical arguments reveal that this phenomenon arises near Mott insulating solutions from the frequency dependence of the self-energy, a behavior not captured by static mean-field theory. We identify distinctive dynamical signatures of correlated altermagnetic states in the spin-resolved optical conductivity, notably a double-peak structure likely linked to high-energy Dirac cone-like bands. Moreover, the spin-resolved response exhibits spin-selective activation at different photon energies, pointing to potential applications in spin-dependent optical control. We also propose perturbations to the model that can induce a topological gap in the spectrum, leading to a transition from topologically trivial to non-trivial states by varying doping, interaction strength, and temperature. |
| title | Dirac points and topological phases in correlated altermagnets |
| topic | Strongly Correlated Electrons Quantum Gases |
| url | https://arxiv.org/abs/2408.14288 |