Topological Mott insulator in the odd-integer filled Anderson lattice model with Hatsugai-Kohmoto interactions

TL;DR

This paper investigates the emergence of topological Mott insulators in an Anderson lattice model with Hatsugai-Kohmoto interactions, highlighting the role of orbital-based interactions and first-order topological transitions without spectral gap closing.

Contribution

It introduces a new analysis of topological Mott insulators focusing on orbital basis interactions and demonstrates their realization under weak correlations, revealing unique transition signatures.

Findings

Topological Mott insulator can form with weak correlations.

Transitions occur without spectral gap closing, indicating first-order transitions.

Spectral function kinks signal topological phase changes.

Abstract

Recently, a quantum anomalous Hall state at odd integer filling in moir\'e stacked MoTe$_2$/WSe$_2$ was convincingly interpreted as a topological Mott insulator state appearing due to strong interactions in {\it band} basis [P. Mai, J. Zhao, B. E. Feldman, and P. W. Phillips, Nat. Commun. {\bf 14}, 5999 (2023)]. In this work, we aim to analyze the formation of a topological Mott insulator due to interactions in {\it orbital} basis instead, being more natural for systems where interactions originate from the character of $f$ or $d$ orbitals rather than band flatness. For that reason, we study an odd-integer filled Anderson lattice model incorporating odd-parity hybridization between orbitals with different degrees of correlations introduced in the Hatsugai-Kohmoto spirit. We demonstrate that a topological Mott insulating state can be realized in a considered model only when weak intra- and inter-orbital correlations involving dispersive states are taken into account. Interestingly, we find that all topological transitions between trivial and topological Mott insulating phases are not accompanied by a spectral gap closing, consistent with a phenomenon called {\it first-order topological transition}. Instead, they are signaled by a kink developed in spectral function at one of the time reversal invariant momenta. We believe that our approach can provide insightful phenomenology of topological Mott insulators in spin-orbit coupled $f$ or $d$ electron systems.