From weakly interacting spinons to tightly bound triplons in the frustrated quantum spin-Peierls chain

Fuente: arXiv
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Main Authors: Park, Pyeongjae, Xiao, Bo, Górnicka, Karolina, May, Andrew F., Yan, Jiaqiang, Kajimoto, Ryoichi, Nakamura, Mitsutaka, Stone, Matthew B., Halász, Gábor B., Christianson, Andrew D.
Format: Preprint
Published: 2025
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author Park, Pyeongjae
Xiao, Bo
Górnicka, Karolina
May, Andrew F.
Yan, Jiaqiang
Kajimoto, Ryoichi
Nakamura, Mitsutaka
Stone, Matthew B.
Halász, Gábor B.
Christianson, Andrew D.
author_facet Park, Pyeongjae
Xiao, Bo
Górnicka, Karolina
May, Andrew F.
Yan, Jiaqiang
Kajimoto, Ryoichi
Nakamura, Mitsutaka
Stone, Matthew B.
Halász, Gábor B.
Christianson, Andrew D.
contents Fractionalized quasiparticles and their confinement into emergent bound states lie at the heart of modern quantum magnetism. While the evolution into magnonic bound states has been well characterized, experimental insight into the analogous transition to triplons remains limited. Here, using high-resolution neutron spectroscopy and state-of-the-art spin dynamics simulations, we uncover the transformation from weakly interacting spinons to tightly bound triplons in the spin-Peierls compound CuGeO3. Quantitative comparisons between the measured spectra and tensor network simulations reveal substantial next-nearest-neighbor frustration and weak external dimerization, placing the system deep within the spontaneously dimerized regime and near the exactly solvable Majumdar-Ghosh point. We further show an energy- and temperature-dependent evolution between two contrasting quasiparticle regimes: deconfined spinons with markedly suppressed interactions by frustration, and coherent triplonic bound states with no observable spinon degrees of freedom. Remarkably, triplon character persists into the two-particle regime, forming a structured two-triplon continuum with a spectral feature associated with a van Hove singularity at its lower boundary. These findings challenge the conventional view that robust triplons require strong external dimerization and demonstrate how the interplay between frustration and dimerization can reshape fractionalization and confinement.
format Preprint
id arxiv_https___arxiv_org_abs_2507_19412
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle From weakly interacting spinons to tightly bound triplons in the frustrated quantum spin-Peierls chain
Park, Pyeongjae
Xiao, Bo
Górnicka, Karolina
May, Andrew F.
Yan, Jiaqiang
Kajimoto, Ryoichi
Nakamura, Mitsutaka
Stone, Matthew B.
Halász, Gábor B.
Christianson, Andrew D.
Strongly Correlated Electrons
Materials Science
Fractionalized quasiparticles and their confinement into emergent bound states lie at the heart of modern quantum magnetism. While the evolution into magnonic bound states has been well characterized, experimental insight into the analogous transition to triplons remains limited. Here, using high-resolution neutron spectroscopy and state-of-the-art spin dynamics simulations, we uncover the transformation from weakly interacting spinons to tightly bound triplons in the spin-Peierls compound CuGeO3. Quantitative comparisons between the measured spectra and tensor network simulations reveal substantial next-nearest-neighbor frustration and weak external dimerization, placing the system deep within the spontaneously dimerized regime and near the exactly solvable Majumdar-Ghosh point. We further show an energy- and temperature-dependent evolution between two contrasting quasiparticle regimes: deconfined spinons with markedly suppressed interactions by frustration, and coherent triplonic bound states with no observable spinon degrees of freedom. Remarkably, triplon character persists into the two-particle regime, forming a structured two-triplon continuum with a spectral feature associated with a van Hove singularity at its lower boundary. These findings challenge the conventional view that robust triplons require strong external dimerization and demonstrate how the interplay between frustration and dimerization can reshape fractionalization and confinement.
title From weakly interacting spinons to tightly bound triplons in the frustrated quantum spin-Peierls chain
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2507.19412