Phonon spectrum in the spin-Peierls phase of CuGeO$_3$

Fuente: arXiv
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Autores principales: Spitz, L., Razpopov, A., Biswas, S., Lane, H., Nikitin, S. E., Iida, K., Kajimoto, R., Fujita, M., Arai, M., Mourigal, M., Rüegg, Ch., Valentí, R., Normand, B.
Formato: Preprint
Publicado: 2025
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author Spitz, L.
Razpopov, A.
Biswas, S.
Lane, H.
Nikitin, S. E.
Iida, K.
Kajimoto, R.
Fujita, M.
Arai, M.
Mourigal, M.
Rüegg, Ch.
Valentí, R.
Normand, B.
author_facet Spitz, L.
Razpopov, A.
Biswas, S.
Lane, H.
Nikitin, S. E.
Iida, K.
Kajimoto, R.
Fujita, M.
Arai, M.
Mourigal, M.
Rüegg, Ch.
Valentí, R.
Normand, B.
contents CuGeO$_3$ has long been studied as a prototypical example of the spin-Peierls transition in a $S = 1/2$ Heisenberg chain. Despite intensive investigation of this quasi-one-dimensional material, systematic measurements and calculations of the phonon excitations in the dimerized phase have not to date been possible, leaving certain aspects of the spin-Peierls phenomenon unresolved. We perform state-of-the-art density functional theory (DFT) calculations to compute the electronic structure and phonon dynamics in the low-temperature dimerized phase. We also perform high-resolution neutron spectroscopy to measure the full phonon spectrum over multiple Brillouin zones. We find excellent agreement between our numerical and experimental results that extend to all measurement temperatures. Notable features of our phonon spectra include a number of steeply dispersive modes, nonmonotonic dispersion features, and specific phonon anticrossings, which we relate to the mode eigenvectors. By calculating the magnetic interactions within DFT and studying the effects of different phonon modes on the superexchange paths, we discuss the possibility of observing spin-phonon hybridization effects in experiments performed both in and out of equilibrium.
format Preprint
id arxiv_https___arxiv_org_abs_2507_12409
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Phonon spectrum in the spin-Peierls phase of CuGeO$_3$
Spitz, L.
Razpopov, A.
Biswas, S.
Lane, H.
Nikitin, S. E.
Iida, K.
Kajimoto, R.
Fujita, M.
Arai, M.
Mourigal, M.
Rüegg, Ch.
Valentí, R.
Normand, B.
Strongly Correlated Electrons
CuGeO$_3$ has long been studied as a prototypical example of the spin-Peierls transition in a $S = 1/2$ Heisenberg chain. Despite intensive investigation of this quasi-one-dimensional material, systematic measurements and calculations of the phonon excitations in the dimerized phase have not to date been possible, leaving certain aspects of the spin-Peierls phenomenon unresolved. We perform state-of-the-art density functional theory (DFT) calculations to compute the electronic structure and phonon dynamics in the low-temperature dimerized phase. We also perform high-resolution neutron spectroscopy to measure the full phonon spectrum over multiple Brillouin zones. We find excellent agreement between our numerical and experimental results that extend to all measurement temperatures. Notable features of our phonon spectra include a number of steeply dispersive modes, nonmonotonic dispersion features, and specific phonon anticrossings, which we relate to the mode eigenvectors. By calculating the magnetic interactions within DFT and studying the effects of different phonon modes on the superexchange paths, we discuss the possibility of observing spin-phonon hybridization effects in experiments performed both in and out of equilibrium.
title Phonon spectrum in the spin-Peierls phase of CuGeO$_3$
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2507.12409