Correlated spinless fermions on the honeycomb lattice revisited

• DOI: 10.1103/physrevb.92.155137
• Publication Date: 2015-10-22T13:12:40Z
• Authors: Daniel D. Scherer; Michael M. Scherer; Carsten Honerkamp
• Keywords: Condensed Matter - Strongly Correlated Electrons; Strongly Correlated Electrons (cond-mat.str-el); 0103 physical sciences; FOS: Physical sciences; 01 natural sciences

9 pages, 8 figures<br/>We investigate the quantum many-body instabilities of the extended Hubbard model for spinless fermions on the honeycomb lattice with repulsive nearest-neighbor and 2nd nearest-neighbor density-density interactions. Recent exact diagonalization and infinite density matrix renormalization group results suggest that a putative topological Mott insulator phase driven by the 2nd nearest-neighbor repulsion is suppressed, while other numerically exact approaches support the topological Mott insulator scenario. In the present work, we employ the functional renormalization group (fRG) for correlated fermionic systems. Our fRG results hint at a strong suppression of the scattering processes stabilizing the topological Mott insulator. From analyzing the effects of fermionic fluctuations, we obtain a phase diagram which is the result of the competition of various charge ordering instabilities.<br/>