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TT: Fachverband Tiefe Temperaturen

TT 13: Correlated Electrons: Method Development I

TT 13.3: Vortrag

Montag, 9. März 2026, 15:30–15:45, HSZ/0101

Uncovering correlated topological phases via a cluster-diagrammatic approach — •Félix Fossati and Evgeny Stepanov — CPHT, CNRS, École polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France

Topological phases exhibit remarkable properties, including protected conducting edge states and robustness against local perturbations. Most studies of topological phenomena have focused on the non-interacting limit, where complete topological classification can be done using a single-particle band structure. While topological properties are known to be robust against weak interactions and disorder, a fundamental question remains: can electronic correlations themselves induce topological phases starting from a trivial non-interacting system? In this work, we address this question by extending the diagrammatic D-TRILEX method to a two-site cluster DMFT reference system. This approach therefore enables capturing short-range correlations non-perturbatively, while treating long-range correlations diagrammatically beyond the cluster DMFT level. We apply our method to the one-dimensional Hubbard model and demonstrate that, by tuning the strength of the non-local Coulomb interaction, our approach captures the formation of both the bond-order-wave (BOW) and the charge-density-wave (CDW) states. We show that the BOW phase can be mapped onto the Su-Schrieffer-Heeger model, while the combined CDW+BOW state corresponds to a Rice-Mele model. The non-trivial topological character of these interaction-induced phases is confirmed by the presence of localised edge states.

Keywords: Cluster DMFT; Diagrammatic method; Topological phase; Interaction-driven phase; Non-local order parameter