Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr14−xCaxCu24O41 ladders

Y. Tseng; J. Thomas; W. Zhang; E. Paris; P. Puphal; R. Bag; G. Deng; T. C. Asmara; V. N. Strocov; S. Singh; E. Pomjakushina; U. Kumar; A. Nocera; H. M. Rønnow; S. Johnston; T. Schmitt

doi:10.1038/s41535-022-00502-1

Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr_14−xCa_xCu₂₄O₄₁ ladders

Y. Tseng
, J. Thomas
, W. Zhang
, E. Paris
, P. Puphal
, R. Bag
, G. Deng
, T. C. Asmara
, V. N. Strocov
, S. Singh
, E. Pomjakushina
, U. Kumar
, A. Nocera
, H. M. Rønnow
, S. Johnston
, T. Schmitt

Research output: Contribution to journal › Article › peer-review

8 Scopus citations

Abstract

We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr_14−xCa_xCu₂₄O₄₁ (SCCO) using Cu L₃-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with high (x = 12.2) and without (x = 0) Ca content, we track the evolution of the magnetic excitations from collective two-triplon (2 T) excitations (x = 0) to weakly-dispersive gapped modes at an energy of 280 meV (x = 12.2). Density matrix renormalization group (DMRG) calculations of the RIXS response in the doped ladders suggest that the flat magnetic dispersion and damped excitation profile observed at x = 12.2 originates from enhanced hole localization. This interpretation is supported by polarization-dependent RIXS measurements, where we disentangle the spin-conserving ΔS = 0 scattering from the predominant ΔS = 1 spin-flip signal in the RIXS spectra. The results show that the low-energy weight in the ΔS = 0 channel is depleted when Sr is replaced by Ca, consistent with a reduced carrier mobility. Our results demonstrate that off-ladder impurities can affect both the low-energy magnetic excitations and superconducting correlations in the CuO₄ plaquettes. Finally, our study characterizes the magnetic and charge fluctuations in the phase from which superconductivity emerges in SCCO at elevated pressures.

Original language	English
Article number	92
Journal	npj Quantum Materials
Volume	7
Issue number	1
DOIs	https://doi.org/10.1038/s41535-022-00502-1
State	Published - Dec 2022
Externally published	Yes

Funding

The experiments have been performed at the ADRESS beamline of the Swiss Light Source at the Paul Scherrer Institut (PSI). The work at PSI is supported by the Swiss National Science Foundation through project no. 200021_178867, and the Sinergia network Mott Physics Beyond the Heisenberg Model (MPBH) (SNSF Research Grants CRSII2_160765/1 and CRSII2_141962). T.C.A. acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 701647 (PSI-FELLOW-II-3i program). Y.T. and T.S. would like to thank V. Bisogni for valuable discussions. A.N. acknowledges, in part, funding from the Max Planck-UBC-UTokyo Center for Quantum Materials and the Canada First Research Excellence Fund, Quantum Materials and Future Technologies Program. J.T. and S.J. are supported by the National Science Foundation under Grant No. DMR-1842056. This work used computational resources supported by the University of Tennessee and Oak Ridge National Laboratory Joint Institute for Computational Sciences, and computational resources and services provided by Advanced Research Computing at the University of British Columbia.

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Tseng, Y., Thomas, J., Zhang, W., Paris, E., Puphal, P., Bag, R., Deng, G., Asmara, T. C., Strocov, V. N., Singh, S., Pomjakushina, E., Kumar, U., Nocera, A., Rønnow, H. M., Johnston, S., & Schmitt, T. (2022). Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr_14−xCa_xCu₂₄O₄₁ ladders. npj Quantum Materials, 7(1), Article 92. https://doi.org/10.1038/s41535-022-00502-1

@article{eb460c9162914c7d84c5d544d2d80d31,

title = "Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr14−xCaxCu24O41 ladders",

abstract = "We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr14−xCaxCu24O41 (SCCO) using Cu L3-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with high (x = 12.2) and without (x = 0) Ca content, we track the evolution of the magnetic excitations from collective two-triplon (2 T) excitations (x = 0) to weakly-dispersive gapped modes at an energy of 280 meV (x = 12.2). Density matrix renormalization group (DMRG) calculations of the RIXS response in the doped ladders suggest that the flat magnetic dispersion and damped excitation profile observed at x = 12.2 originates from enhanced hole localization. This interpretation is supported by polarization-dependent RIXS measurements, where we disentangle the spin-conserving ΔS = 0 scattering from the predominant ΔS = 1 spin-flip signal in the RIXS spectra. The results show that the low-energy weight in the ΔS = 0 channel is depleted when Sr is replaced by Ca, consistent with a reduced carrier mobility. Our results demonstrate that off-ladder impurities can affect both the low-energy magnetic excitations and superconducting correlations in the CuO4 plaquettes. Finally, our study characterizes the magnetic and charge fluctuations in the phase from which superconductivity emerges in SCCO at elevated pressures.",

author = "Y. Tseng and J. Thomas and W. Zhang and E. Paris and P. Puphal and R. Bag and G. Deng and Asmara, \{T. C.\} and Strocov, \{V. N.\} and S. Singh and E. Pomjakushina and U. Kumar and A. Nocera and R{\o}nnow, \{H. M.\} and S. Johnston and T. Schmitt",

note = "Publisher Copyright: {\textcopyright} 2022, The Author(s).",

year = "2022",

month = dec,

doi = "10.1038/s41535-022-00502-1",

language = "English",

volume = "7",

journal = "npj Quantum Materials",

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Tseng, Y, Thomas, J, Zhang, W, Paris, E, Puphal, P, Bag, R, Deng, G, Asmara, TC, Strocov, VN, Singh, S, Pomjakushina, E, Kumar, U, Nocera, A, Rønnow, HM, Johnston, S & Schmitt, T 2022, 'Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr_14−xCa_xCu₂₄O₄₁ ladders', npj Quantum Materials, vol. 7, no. 1, 92. https://doi.org/10.1038/s41535-022-00502-1

TY - JOUR

T1 - Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr14−xCaxCu24O41 ladders

AU - Tseng, Y.

AU - Thomas, J.

AU - Zhang, W.

AU - Paris, E.

AU - Puphal, P.

AU - Bag, R.

AU - Deng, G.

AU - Asmara, T. C.

AU - Strocov, V. N.

AU - Singh, S.

AU - Pomjakushina, E.

AU - Kumar, U.

AU - Nocera, A.

AU - Rønnow, H. M.

AU - Johnston, S.

AU - Schmitt, T.

PY - 2022/12

Y1 - 2022/12

N2 - We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr14−xCaxCu24O41 (SCCO) using Cu L3-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with high (x = 12.2) and without (x = 0) Ca content, we track the evolution of the magnetic excitations from collective two-triplon (2 T) excitations (x = 0) to weakly-dispersive gapped modes at an energy of 280 meV (x = 12.2). Density matrix renormalization group (DMRG) calculations of the RIXS response in the doped ladders suggest that the flat magnetic dispersion and damped excitation profile observed at x = 12.2 originates from enhanced hole localization. This interpretation is supported by polarization-dependent RIXS measurements, where we disentangle the spin-conserving ΔS = 0 scattering from the predominant ΔS = 1 spin-flip signal in the RIXS spectra. The results show that the low-energy weight in the ΔS = 0 channel is depleted when Sr is replaced by Ca, consistent with a reduced carrier mobility. Our results demonstrate that off-ladder impurities can affect both the low-energy magnetic excitations and superconducting correlations in the CuO4 plaquettes. Finally, our study characterizes the magnetic and charge fluctuations in the phase from which superconductivity emerges in SCCO at elevated pressures.

AB - We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr14−xCaxCu24O41 (SCCO) using Cu L3-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with high (x = 12.2) and without (x = 0) Ca content, we track the evolution of the magnetic excitations from collective two-triplon (2 T) excitations (x = 0) to weakly-dispersive gapped modes at an energy of 280 meV (x = 12.2). Density matrix renormalization group (DMRG) calculations of the RIXS response in the doped ladders suggest that the flat magnetic dispersion and damped excitation profile observed at x = 12.2 originates from enhanced hole localization. This interpretation is supported by polarization-dependent RIXS measurements, where we disentangle the spin-conserving ΔS = 0 scattering from the predominant ΔS = 1 spin-flip signal in the RIXS spectra. The results show that the low-energy weight in the ΔS = 0 channel is depleted when Sr is replaced by Ca, consistent with a reduced carrier mobility. Our results demonstrate that off-ladder impurities can affect both the low-energy magnetic excitations and superconducting correlations in the CuO4 plaquettes. Finally, our study characterizes the magnetic and charge fluctuations in the phase from which superconductivity emerges in SCCO at elevated pressures.

UR - https://www.scopus.com/pages/publications/85138123285

U2 - 10.1038/s41535-022-00502-1

DO - 10.1038/s41535-022-00502-1

M3 - Article

AN - SCOPUS:85138123285

SN - 2397-4648

VL - 7

JO - npj Quantum Materials

JF - npj Quantum Materials

IS - 1

M1 - 92

ER -

Crossover of high-energy spin fluctuations from collective triplons to localized magnetic excitations in Sr_14−xCa_xCu₂₄O₄₁ ladders

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