Altermagnetism and superconductivity in a multiorbital t-J model

Fuente: arXiv
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Autores principales: Bose, Anjishnu, Vadnais, Samuel, Paramekanti, Arun
Formato: Preprint
Publicado: 2024
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author Bose, Anjishnu
Vadnais, Samuel
Paramekanti, Arun
author_facet Bose, Anjishnu
Vadnais, Samuel
Paramekanti, Arun
contents Motivated by exploring doped multi-orbital antiferromagnets (AFMs) and altermagnets (ALMs) we explore minimal $t$-$J$ models on the square-octagon lattice which favor such collinear magnetic orders in the regime where spin exchange dominates. While the AFM order breaks translational and time-reversal symmetries, the ALM state (equivalently, a `$d$-wave ferromagnet') features multipolar order which separately breaks time-reversal and crystal rotation symmetries but preserves their product leading to spin-split bands with zero net magnetization. We study the mean field phase diagram of these models as we vary doping and interactions, discovering regimes of weak and strong ALM order, superconductivity including uniform $s$-wave and $d$-wave pairing states, incipient $d$-wave pair density wave order, and phases with coexisting singlet-triplet pairing and AFM/ALM orders which appear unstable to phase separation and could host stripe order with longer-range interactions. We study the mean field phase diagram of these multiorbital models as we vary doping and interactions, discovering two types of ALM order: (i) itinerant weak-coupling ALM metals driven by quasi-1D van Hove singularities, as well as (ii) strong ALM order at half-filling. We also find regimes of superconductivity including uniform $s$-wave and $d$-wave pairing states, incipient $d_{xy}$-wave pair density wave order, and uniform phases with coexisting singlet-triplet pairing and ALM order. Our inhomogeneous mean field theory approach reveals that the coexistence phases are unstable to phase separation, but longer-range interactions could lead to stripe order. Our results may be relevant to doping or pressure studies of multiorbital ALM materials.
format Preprint
id arxiv_https___arxiv_org_abs_2403_17050
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Altermagnetism and superconductivity in a multiorbital t-J model
Bose, Anjishnu
Vadnais, Samuel
Paramekanti, Arun
Strongly Correlated Electrons
Superconductivity
Motivated by exploring doped multi-orbital antiferromagnets (AFMs) and altermagnets (ALMs) we explore minimal $t$-$J$ models on the square-octagon lattice which favor such collinear magnetic orders in the regime where spin exchange dominates. While the AFM order breaks translational and time-reversal symmetries, the ALM state (equivalently, a `$d$-wave ferromagnet') features multipolar order which separately breaks time-reversal and crystal rotation symmetries but preserves their product leading to spin-split bands with zero net magnetization. We study the mean field phase diagram of these models as we vary doping and interactions, discovering regimes of weak and strong ALM order, superconductivity including uniform $s$-wave and $d$-wave pairing states, incipient $d$-wave pair density wave order, and phases with coexisting singlet-triplet pairing and AFM/ALM orders which appear unstable to phase separation and could host stripe order with longer-range interactions. We study the mean field phase diagram of these multiorbital models as we vary doping and interactions, discovering two types of ALM order: (i) itinerant weak-coupling ALM metals driven by quasi-1D van Hove singularities, as well as (ii) strong ALM order at half-filling. We also find regimes of superconductivity including uniform $s$-wave and $d$-wave pairing states, incipient $d_{xy}$-wave pair density wave order, and uniform phases with coexisting singlet-triplet pairing and ALM order. Our inhomogeneous mean field theory approach reveals that the coexistence phases are unstable to phase separation, but longer-range interactions could lead to stripe order. Our results may be relevant to doping or pressure studies of multiorbital ALM materials.
title Altermagnetism and superconductivity in a multiorbital t-J model
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2403.17050