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Andrey E. Antipov

Publications and source records attributed to Andrey E. Antipov.

20 records · Page 2Linked to original sources

Critical Exponents of Strongly Correlated Fermion Systems from Diagrammatic Multi-Scale Methods

Self-consistent dynamical approximations for strongly correlated fermion systems are particularly successful in capturing the dynamical competition of local correlations. In these, the effect of spatially extended degrees of freedom is usually only taken into account in a mean field fashion or as a secondary effect. As a result, critical exponents associated with phase transitions have mean field character. Here, we demonstrate that diagrammatic multi-scale methods anchored around local approximations are indeed capable of capturing the non mean-field nature of the critical point of the lattice model encoded in a non-vanishing anomalous dimension, and to correctly describe the transition to mean field like behavior as the number of spatial dimensions increases.

cond-mat.str-el↗

Competing phases of the Hubbard model on a triangular lattice -- insights from the entropy

Based on the ladder dual-fermion approach, we present a comprehensive study of the phases of the isotropic Hubbard model on the triangular lattice. We find a rich phase diagram containing most of the phases that have already been experimentally observed in systems where the interplay between geometric frustration and electronic correlations is important: paramagnetic metal, paramagnetic insulator, Mott-insulator with $120^{\circ}$ antiferromagnetic and a non-magnetic insulating state, i.e. possibly a spin liquid state. This establishes that the Hubbard model on frustrated lattices can serve as a minimal model to address the intricate interplay of frustration and correlation. We also show that entropic considerations can be successfully used for understanding many striking features of the triangular systems, such as the large thermopower found in Na$_{x}$CoO$_{2}\cdot$$y$H$_{2}$O.

cond-mat.str-el↗