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Abstract
We study the KaneMeleHubbard model with an additional inversionsymmetrybreaking term. Using the topological Hamiltonian approach, we calculate the Z 2 invariant of the system as function of spinorbit coupling, Hubbard interaction U , and inversionsymmetrybreaking onsite potential. The phase diagram calculated in that way shows that, on the one hand, a large term of the latter kind destroys the topological nontrivial state. On the other hand, however, this inversionsymmetrybreaking field can enhance the topological state since for moderate values the transition from the nontrivial topological to the trivial Mott insulator is pushed to larger values of interaction U . This feature of an enhanced topological state is also found on honeycomb ribbons. With inversion
symmetry, the edge of the zigzag ribbon is magnetic for any value of U . This magnetic moment destroys the gapless edge mode. Lifting inversion symmetry allows for a finite region in interaction strength U below which gapless edge modes exist.
symmetry, the edge of the zigzag ribbon is magnetic for any value of U . This magnetic moment destroys the gapless edge mode. Lifting inversion symmetry allows for a finite region in interaction strength U below which gapless edge modes exist.
Original language  English 

Article number  165169 
Journal  Physical Review / B 
Volume  94 
DOIs  
Publication status  Published  26 Oct 2016 
Fields of Expertise
 Advanced Materials Science
Treatment code (Nähere Zuordnung)
 Basic  Fundamental (Grundlagenforschung)
 Theoretical
Cooperations
 NAWI Graz
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Projects
 1 Active

FWF  TOPOMAT  Topological states of matter from first principles
1/11/14 → 31/10/22
Project: Research project