Impurity-induced Mott ring states and Mott zeros ring states in the Hubbard operator formalism

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Main Authors: Pangburn, Emile, Banerjee, Anurag, Pépin, Catherine, Bena, Cristina
Format: Preprint
Published: 2025
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author Pangburn, Emile
Banerjee, Anurag
Pépin, Catherine
Bena, Cristina
author_facet Pangburn, Emile
Banerjee, Anurag
Pépin, Catherine
Bena, Cristina
contents We study the formation of subgap impurity states in strongly correlated Mott insulators. We use a composite operator method that gives us access to both the bulk Green's function, as well as to the real-space Green's function in the presence of an impurity. Similar to the non-interacting systems, we show that the formation of impurity subgap states at large impurity potential ("Mott ring states") depends rather on the band-mixing, than on the topological character of the system. Thus even a trivial Mott insulator can under certain conditions exhibit ring states. For the system studied here the band mixing is that between the holon and doublon elementary excitations rather than an orbital mixing. Moreover we study the formation of bands of zeros in the correlated Green's function, believed to exhibit a free quasiparticle-like behavior. We show that in the presence of an impurity the same conclusion can be applied, i.e. ``Mott zeros ring states" form in the presence of topological bands of zeros, but also for trivial quasi-flat bands of zeros with band mixing.
format Preprint
id arxiv_https___arxiv_org_abs_2503_05870
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Impurity-induced Mott ring states and Mott zeros ring states in the Hubbard operator formalism
Pangburn, Emile
Banerjee, Anurag
Pépin, Catherine
Bena, Cristina
Strongly Correlated Electrons
We study the formation of subgap impurity states in strongly correlated Mott insulators. We use a composite operator method that gives us access to both the bulk Green's function, as well as to the real-space Green's function in the presence of an impurity. Similar to the non-interacting systems, we show that the formation of impurity subgap states at large impurity potential ("Mott ring states") depends rather on the band-mixing, than on the topological character of the system. Thus even a trivial Mott insulator can under certain conditions exhibit ring states. For the system studied here the band mixing is that between the holon and doublon elementary excitations rather than an orbital mixing. Moreover we study the formation of bands of zeros in the correlated Green's function, believed to exhibit a free quasiparticle-like behavior. We show that in the presence of an impurity the same conclusion can be applied, i.e. ``Mott zeros ring states" form in the presence of topological bands of zeros, but also for trivial quasi-flat bands of zeros with band mixing.
title Impurity-induced Mott ring states and Mott zeros ring states in the Hubbard operator formalism
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2503.05870