Change of an insulator's topological properties by a Hubbard interaction

• Type: Article in International Scientific Journal
• Date: 2013

Authors

Araujo, MAN (Author) Other; Eduardo V Castro (Author) Other; Sacramento, PD (Author) Other

Journal

Title: Physical Review B - Condensed Matter and Materials Physics

Vol. 87

ISSN: 1098-0121

Publisher: American Physical Society

Indexing

ISI Web of Knowledge - 26 Citations

Scopus - 27 Citations

Other information

Authenticus ID: P-002-0J4

DOI: 10.1103/physrevb.87.085109

Abstract (EN): 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) over bar, smaller than that for the Mott transition. Two different situations may then occur: Either the anomalous Hall conductivity sigma(xy) changes abruptly at (U) over bar, as the system undergoes a transition from one topologically nontrivial insulator to another, or the transition is through an anomalous Hall metal, and sigma(xy) 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 Z(2) topological insulator. The topological number. then changes at a critical coupling (U) over bar and the quantized spin Hall response changes abruptly. DOI: 10.1103/PhysRevB.87.085109

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5