Project Details
Projekt
Modeling the interplay of non-locality, topology and disorder in correlated systems
Subject Area
Theoretical Condensed Matter Physics
Term
since 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 449872909
Disorder is ubiquitous to many correlated materials. While in the past it has been considered as an aspect to be avoided in materials' design, it is often of central importance for the manifestation of some of the notable properties of the systems. Gaining a microscopic understanding of the influence of disorder on the electronic, magnetic and topological properties of correlated materials is, however, a challenging task due to the many-body character of correlations. Our goal for the second funding period is to explore correlated phases of matter by addressing the interplay of correlations, non-locality, topology and - as a further aspect - disorder, through microscopic modeling. To address this interplay we will consider and further develop a combination of \textit{ab initio} density functional theory (DFT), projective Wannier functions and many-body methods such as dynamical mean-field theory (DMFT), the two-particle self-consistent approach (TPSC), the triply irreducible local expansion (TRILEX), cellular DMFT (CDMFT), a Blackman-Esterling-Berk molecular potential extension of CDMFT (C-CDMFT), and machine learning techniques. Our focus will be on moiré, triangular-, and kagome-lattice platforms in collaboration with P1, P3, and P5-P8. We will proceed along three lines: (i) We will investigate exemplary many-body models containing onsite potential disorder and disorder in hopping parameters to test and further develop our methods. A choice of models are: topological heavy-fermion models, relevant for moiré systems, multi-orbital (extended) Hubbard models on the kagome and triangular lattice (with longer-range interactions), relevant for organic charge transfer salts and moiré transition-metal dichalcogenides, as well as Haldane-Hubbard, Kane-Mele-Hubbard models and extensions. (ii) We will perform microscopic modeling from first principles of a choice of materials relevant in QUAST where the concepts and methods developed and applied to simple models in (i) will now be used for more realistic calculations. These are, in particular, moiré systems in collaboration with P5, Cr-based kagome systems with filling near the flat band in collaboration with P3 and P5, (doped) transition-metal dichalcogenides in collaboration with P6, and charge-transfer salts. (iii) We will continue our efforts to scan and diagnose topologically non-trivial phases in interacting systems in collaboration with P3, P5, and P8.
DFG Programme
Research Units
