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Main Authors: Voleti, Sreekar, Wandler, F David, Paramekanti, Arun
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2303.04169
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author Voleti, Sreekar
Wandler, F David
Paramekanti, Arun
author_facet Voleti, Sreekar
Wandler, F David
Paramekanti, Arun
contents The quest for exotic quantum magnetic ground states, including the Kitaev spin liquid and quantum spin-ices, has led to the discovery of several quantum materials where low energy pseudospin-$1/2$ doublets arise from the splitting of spin-orbit entangled multiplets with higher degeneracy. Such systems include $d$-orbital and $f$-orbital Mott insulators. When the gap between the low energy pseudospin-$1/2$ levels and the excited levels of the multiplet or `excitons' is not large, the effective low-energy exchange interactions between the low energy pseudospin-$1/2$ moments can acquire significant corrections from coupling to the excitons. We extract these corrections using higher order perturbation theory as well as an exact Schrieffer-Wolff transformation. Such corrections can impact the exchange matrix for the low energy pseudospin-$1/2$ levels by renormalizing the strength and the sign of Heisenberg exchange or Ising anisotropies, and potentially even inducing bond-anisotropic couplings such as Kitaev-$Γ$ exchange interactions. We discuss recent experiments on various cobaltate and osmate materials which hint at the ubiquity and importance of this physics.
format Preprint
id arxiv_https___arxiv_org_abs_2303_04169
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Impact of gapped spin-orbit excitons on low energy pseudospin exchange interactions
Voleti, Sreekar
Wandler, F David
Paramekanti, Arun
Strongly Correlated Electrons
The quest for exotic quantum magnetic ground states, including the Kitaev spin liquid and quantum spin-ices, has led to the discovery of several quantum materials where low energy pseudospin-$1/2$ doublets arise from the splitting of spin-orbit entangled multiplets with higher degeneracy. Such systems include $d$-orbital and $f$-orbital Mott insulators. When the gap between the low energy pseudospin-$1/2$ levels and the excited levels of the multiplet or `excitons' is not large, the effective low-energy exchange interactions between the low energy pseudospin-$1/2$ moments can acquire significant corrections from coupling to the excitons. We extract these corrections using higher order perturbation theory as well as an exact Schrieffer-Wolff transformation. Such corrections can impact the exchange matrix for the low energy pseudospin-$1/2$ levels by renormalizing the strength and the sign of Heisenberg exchange or Ising anisotropies, and potentially even inducing bond-anisotropic couplings such as Kitaev-$Γ$ exchange interactions. We discuss recent experiments on various cobaltate and osmate materials which hint at the ubiquity and importance of this physics.
title Impact of gapped spin-orbit excitons on low energy pseudospin exchange interactions
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2303.04169