The kagome Hubbard model from a functional renormalization group perspective

arXiv (Cornell University)

Abstract

The recent discovery of a variety of intricate electronic order in kagome metals has sprouted significant theoretical and experimental interest. From an electronic perspective on the potential microscopic origin of these phases, the most basic model is given by a Hubbard model on the kagome lattice. We employ functional renormalization group (FRG) to analyze the kagome Hubbard model. Through our methodological refinement of FRG both within its N-patch and truncated unity formulation, we resolve previous discrepancies of different FRG approaches (Wang et al., 2013 vs. Kiesel et al., 2013), and analyze both the pure ($p$-type) and mixed ($m$-type) van Hove fillings of the kagome lattice. We further study the RG flow into symmetry broken phases to identify the energetically preferred linear combination of the respective order parameter without any need for additional mean field analysis. Our findings suggest some consistency with recent experiments, and underline the richness of electronic phases already found in the kagome Hubbard model. We also provide a no-go theorem for a complex charge bond ordered phase in the single orbital kagome Hubbard model, suggesting that this model cannot capture aspects of orbital current phases.

Authors 8

1. Jonas B. Profe Aachen Institut für Theorie der Statistischen Physik

   Goethe University Frankfurt · RWTH Aachen University

   Affiliation as printed

   Institut für Theorie der Statistischen Physik , RWTH Aachen University and JARA-Fundamentals of Future Information Technology , 52056 Aachen , Germany

   Institute for Theoretical Physics , Goethe University Frankfurt , Max-von-Laue-Straße 1 , D-60438 Frankfurt a.M. , Germany

2. Lennart Klebl

   Universität Hamburg

   Affiliation as printed

   I. Institute for Theoretical Physics , Universität Hamburg , Hamburg , Germany

3. Francesco Grandi Aachen Institut für Theorie der Statistischen Physik

   RWTH Aachen University

   Affiliation as printed

   Institut für Theorie der Statistischen Physik , RWTH Aachen University and JARA-Fundamentals of Future Information Technology , 52056 Aachen , Germany

4. Hendrik Hohmann

   University of Würzburg · Complexity, Topology and Dynamics in Quantum Matter

   Affiliation as printed

   Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat , Universität Würzburg , 97074 Würzburg , Germany

5. Matteo Dürrnagel
6. Tilman Schwemmer

   University of Würzburg · Complexity, Topology and Dynamics in Quantum Matter

   Affiliation as printed

   Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat , Universität Würzburg , 97074 Würzburg , Germany

7. Ronny Thomale

   University of Würzburg · Complexity, Topology and Dynamics in Quantum Matter · Center for Free-Electron Laser Science

   Affiliation as printed

   Center for Free Electron Laser Science , 22761 Hamburg , Germany

   Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat , Universität Würzburg , 97074 Würzburg , Germany

8. Dante Marvin Kennes Aachen Institut für Theorie der Statistischen Physik

   Max Planck Society · Max Planck Institute for the Structure and Dynamics of Matter · RWTH Aachen University

   Affiliation as printed

   Institut für Theorie der Statistischen Physik , RWTH Aachen University and JARA-Fundamentals of Future Information Technology , 52056 Aachen , Germany

   Max Planck Institute for the Structure and Dynamics of Matter ,