Structural transition, spontaneous formation of strong singlet dimers and metamagnetism in $S=3/2$ magnetoelastic spin chains

Fuente: arXiv
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Auteurs principaux: Gazza, C. J., Aligia, A. A., Dobry, A. O., Rossini, G. L., Cabra, D. C.
Format: Preprint
Publié: 2024
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author Gazza, C. J.
Aligia, A. A.
Dobry, A. O.
Rossini, G. L.
Cabra, D. C.
author_facet Gazza, C. J.
Aligia, A. A.
Dobry, A. O.
Rossini, G. L.
Cabra, D. C.
contents We study a one-dimensional antiferromagnetic-elastic model with magnetic ions having spin $S=3/2$. By extensive DMRG computations and complementary analytical methods, we uncover a first-order transition from a homogeneous or weakly-dimerized phase (a situation that could be similar to the well known $S=1/2$ spin-Peierls effect) to a highly distorted phase, driven by the spin-phonon coupling $λ$. The striking characteristic of the second phase, present at large $λ$, is the appearance of weakly ferromagnetic (FM) couplings alternating with strong antiferromagnetic (AFM) ones (we dub it FM-AFM phase) with a ground state close to a direct-product state of singlet dimers sitting on the AFM bonds. The behavior of the spin gap in both phases is studied by DMRG computation and contrasted with bosonization predictions and perturbation theory around the direct product of dimers. In the FM-AFM phase robust magnetization plateaus and metamagnetic jumps show under magnetic fields. The novel phase could be realized in 5d oxides of current interest, with giant spin-phonon coupling. Potential applications of the transition would be associated to the possibility of tuning the transition by external parameters such as striction, magnetic or electric fields, or alloying.
format Preprint
id arxiv_https___arxiv_org_abs_2409_13446
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Structural transition, spontaneous formation of strong singlet dimers and metamagnetism in $S=3/2$ magnetoelastic spin chains
Gazza, C. J.
Aligia, A. A.
Dobry, A. O.
Rossini, G. L.
Cabra, D. C.
Strongly Correlated Electrons
We study a one-dimensional antiferromagnetic-elastic model with magnetic ions having spin $S=3/2$. By extensive DMRG computations and complementary analytical methods, we uncover a first-order transition from a homogeneous or weakly-dimerized phase (a situation that could be similar to the well known $S=1/2$ spin-Peierls effect) to a highly distorted phase, driven by the spin-phonon coupling $λ$. The striking characteristic of the second phase, present at large $λ$, is the appearance of weakly ferromagnetic (FM) couplings alternating with strong antiferromagnetic (AFM) ones (we dub it FM-AFM phase) with a ground state close to a direct-product state of singlet dimers sitting on the AFM bonds. The behavior of the spin gap in both phases is studied by DMRG computation and contrasted with bosonization predictions and perturbation theory around the direct product of dimers. In the FM-AFM phase robust magnetization plateaus and metamagnetic jumps show under magnetic fields. The novel phase could be realized in 5d oxides of current interest, with giant spin-phonon coupling. Potential applications of the transition would be associated to the possibility of tuning the transition by external parameters such as striction, magnetic or electric fields, or alloying.
title Structural transition, spontaneous formation of strong singlet dimers and metamagnetism in $S=3/2$ magnetoelastic spin chains
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2409.13446