2012/08/31 by M. A. N. Araújo, Miguel A. N. Araújo, Eduardo V. Castro +2 · 4 citations
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Condensed matter physics #Fermion #Hubbard model #Lattice (music) #Mathematics #Mott insulator #Mott transition #Physics #Quantum #Quantum many-body systems #Quantum mechanics #Superconductivity #Topological Materials and Phenomena #Topological insulator #Topological order #Topology (electrical circuits) #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.87.085109
published as Phys. Rev. B 87, 085109 (2013) · 5 pages, 3 figures
arxiv created 2012/11/21 · openalex publication_date 2013/02/07 · arxiv updated 2013/02/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We introduce two-dimensional fermionic band models with two orbitals per lattice site, or one spinful orbital, and which have a nonzero topological Chern number that can be changed by varying the ratio of hopping parameters. A topologically nontrivial insulator is then realized if there is one fermion per site. When interactions in the framework of the Hubbard model are introduced, the effective hopping parameters are renormalized and the system's topological number can change at a certain interaction strength, U=U, smaller than that for the Mott transition. Two different situations may then occur: Either the anomalous Hall conductivity \ensuremathσxy changes abruptly at U, as the system undergoes a transition from one topologically nontrivial insulator to another, or the transition is through an anomalous Hall metal, and \ensuremathσxy changes smoothly between two different quantized values as U grows. Restoring time-reversal symmetry by adding spin to spinless models, the half-filled system becomes a ℤ2 topological insulator. The topological number \ensuremathν then changes at a critical coupling U and the quantized spin Hall response changes abruptly.