Tunable magnons of an antiferromagnetic Mott insulator via interfacial metal-insulator transitions

Sujan Shrestha; Maryam Souri; Christopher J. Dietl; Ekaterina M. Pärschke; Maximilian Krautloher; Gabriel A. Calderon Ortiz; Matteo Minola; Xiatong Shi; Alexander V. Boris; Jinwoo Hwang; Giniyat Khaliullin; Gang Cao; Bernhard Keimer; Jong Woo Kim; Jungho Kim; Ambrose Seo

doi:10.1038/s41467-025-58922-z

Tunable magnons of an antiferromagnetic Mott insulator via interfacial metal-insulator transitions

Sujan Shrestha, Maryam Souri, Christopher J. Dietl, Ekaterina M. Pärschke, Maximilian Krautloher, Gabriel A. Calderon Ortiz, Matteo Minola, Xiatong Shi, Alexander V. Boris, Jinwoo Hwang, Giniyat Khaliullin, Gang Cao, Bernhard Keimer, Jong Woo Kim, Jungho Kim, Ambrose Seo

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

Abstract

Antiferromagnetic insulators present a promising alternative to ferromagnets due to their ultrafast spin dynamics essential for low-energy terahertz spintronic device applications. Magnons, i.e., quantized spin waves capable of transmitting information through excitations, serve as a key functional element in this paradigm. However, identifying external mechanisms to effectively tune magnon properties has remained a major challenge. Here we demonstrate that interfacial metal-insulator transitions offer an effective method for controlling the magnons of Sr₂IrO₄, a strongly spin-orbit coupled antiferromagnetic Mott insulator. Resonant inelastic x-ray scattering experiments reveal a significant softening of zone-boundary magnon energies in Sr₂IrO₄ films epitaxially interfaced with metallic 4d transition-metal oxides. Therefore, the magnon dispersion of Sr₂IrO₄ can be tuned by metal-insulator transitions of the 4d transition-metal oxides. We tentatively attribute this non-trivial behavior to a long-range phenomenon mediated by magnon-acoustic phonon interactions. Our experimental findings introduce a strategy for controlling magnons and underscore the need for further theoretical studies to better understand the underlying microscopic interactions between magnons and phonons.

Original language	English
Article number	3592
Journal	Nature Communications
Volume	16
Issue number	1
DOIs	https://doi.org/10.1038/s41467-025-58922-z
State	Published - Dec 2025

Bibliographical note

Publisher Copyright:
© The Author(s) 2025.

Funding

We acknowledge the support of National Science Foundation Grant No. DMR\u22122104296 for sample synthesis and characterization. This research used resources of the Advanced Photon Source; a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Electron microscopy was performed at the Center for Electron Microscopy and Analysis at the Ohio State University supported by National Science Foundation Grant No. DMR\u22121847964. G.C. acknowledges NSF support via Grant No. DMR 2204811. We acknowledge support from the European Research Council under Advanced Grant No. 101141844 (SpecTera) and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through Project No. 107745057-TRR 80.

Funders	Funder number
U.S. Department of Energy Oak Ridge National Laboratory U.S. Department of Energy National Science Foundation National Energy Research Scientific Computing Center
National Science Foundation Office of International Science and Engineering
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China	DMR 2204811
U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China
Deutsche Forschungsgemeinschaft	107745057-TRR 80
Deutsche Forschungsgemeinschaft
Argonne National Laboratory	DMR−1847964, DE-AC02-06CH11357
Argonne National Laboratory
H2020 European Research Council	101141844
H2020 European Research Council

ASJC Scopus subject areas

General Chemistry
General Biochemistry, Genetics and Molecular Biology
General Physics and Astronomy

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10.1038/s41467-025-58922-z

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Shrestha, S., Souri, M., Dietl, C. J., Pärschke, E. M., Krautloher, M., Calderon Ortiz, G. A., Minola, M., Shi, X., Boris, A. V., Hwang, J., Khaliullin, G., Cao, G., Keimer, B., Kim, J. W., Kim, J., & Seo, A. (2025). Tunable magnons of an antiferromagnetic Mott insulator via interfacial metal-insulator transitions. Nature Communications, 16(1), Article 3592. https://doi.org/10.1038/s41467-025-58922-z

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title = "Tunable magnons of an antiferromagnetic Mott insulator via interfacial metal-insulator transitions",

abstract = "Antiferromagnetic insulators present a promising alternative to ferromagnets due to their ultrafast spin dynamics essential for low-energy terahertz spintronic device applications. Magnons, i.e., quantized spin waves capable of transmitting information through excitations, serve as a key functional element in this paradigm. However, identifying external mechanisms to effectively tune magnon properties has remained a major challenge. Here we demonstrate that interfacial metal-insulator transitions offer an effective method for controlling the magnons of Sr2IrO4, a strongly spin-orbit coupled antiferromagnetic Mott insulator. Resonant inelastic x-ray scattering experiments reveal a significant softening of zone-boundary magnon energies in Sr2IrO4 films epitaxially interfaced with metallic 4d transition-metal oxides. Therefore, the magnon dispersion of Sr2IrO4 can be tuned by metal-insulator transitions of the 4d transition-metal oxides. We tentatively attribute this non-trivial behavior to a long-range phenomenon mediated by magnon-acoustic phonon interactions. Our experimental findings introduce a strategy for controlling magnons and underscore the need for further theoretical studies to better understand the underlying microscopic interactions between magnons and phonons.",

author = "Sujan Shrestha and Maryam Souri and Dietl, \{Christopher J.\} and P{\"a}rschke, \{Ekaterina M.\} and Maximilian Krautloher and \{Calderon Ortiz\}, \{Gabriel A.\} and Matteo Minola and Xiatong Shi and Boris, \{Alexander V.\} and Jinwoo Hwang and Giniyat Khaliullin and Gang Cao and Bernhard Keimer and Kim, \{Jong Woo\} and Jungho Kim and Ambrose Seo",

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doi = "10.1038/s41467-025-58922-z",

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Shrestha, S, Souri, M, Dietl, CJ, Pärschke, EM, Krautloher, M, Calderon Ortiz, GA, Minola, M, Shi, X, Boris, AV, Hwang, J, Khaliullin, G, Cao, G, Keimer, B, Kim, JW, Kim, J & Seo, A 2025, 'Tunable magnons of an antiferromagnetic Mott insulator via interfacial metal-insulator transitions', Nature Communications, vol. 16, no. 1, 3592. https://doi.org/10.1038/s41467-025-58922-z

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T1 - Tunable magnons of an antiferromagnetic Mott insulator via interfacial metal-insulator transitions

AU - Shrestha, Sujan

AU - Souri, Maryam

AU - Dietl, Christopher J.

AU - Pärschke, Ekaterina M.

AU - Krautloher, Maximilian

AU - Calderon Ortiz, Gabriel A.

AU - Minola, Matteo

AU - Shi, Xiatong

AU - Boris, Alexander V.

AU - Hwang, Jinwoo

AU - Khaliullin, Giniyat

AU - Cao, Gang

AU - Keimer, Bernhard

AU - Kim, Jong Woo

AU - Kim, Jungho

AU - Seo, Ambrose

PY - 2025/12

Y1 - 2025/12

N2 - Antiferromagnetic insulators present a promising alternative to ferromagnets due to their ultrafast spin dynamics essential for low-energy terahertz spintronic device applications. Magnons, i.e., quantized spin waves capable of transmitting information through excitations, serve as a key functional element in this paradigm. However, identifying external mechanisms to effectively tune magnon properties has remained a major challenge. Here we demonstrate that interfacial metal-insulator transitions offer an effective method for controlling the magnons of Sr2IrO4, a strongly spin-orbit coupled antiferromagnetic Mott insulator. Resonant inelastic x-ray scattering experiments reveal a significant softening of zone-boundary magnon energies in Sr2IrO4 films epitaxially interfaced with metallic 4d transition-metal oxides. Therefore, the magnon dispersion of Sr2IrO4 can be tuned by metal-insulator transitions of the 4d transition-metal oxides. We tentatively attribute this non-trivial behavior to a long-range phenomenon mediated by magnon-acoustic phonon interactions. Our experimental findings introduce a strategy for controlling magnons and underscore the need for further theoretical studies to better understand the underlying microscopic interactions between magnons and phonons.

AB - Antiferromagnetic insulators present a promising alternative to ferromagnets due to their ultrafast spin dynamics essential for low-energy terahertz spintronic device applications. Magnons, i.e., quantized spin waves capable of transmitting information through excitations, serve as a key functional element in this paradigm. However, identifying external mechanisms to effectively tune magnon properties has remained a major challenge. Here we demonstrate that interfacial metal-insulator transitions offer an effective method for controlling the magnons of Sr2IrO4, a strongly spin-orbit coupled antiferromagnetic Mott insulator. Resonant inelastic x-ray scattering experiments reveal a significant softening of zone-boundary magnon energies in Sr2IrO4 films epitaxially interfaced with metallic 4d transition-metal oxides. Therefore, the magnon dispersion of Sr2IrO4 can be tuned by metal-insulator transitions of the 4d transition-metal oxides. We tentatively attribute this non-trivial behavior to a long-range phenomenon mediated by magnon-acoustic phonon interactions. Our experimental findings introduce a strategy for controlling magnons and underscore the need for further theoretical studies to better understand the underlying microscopic interactions between magnons and phonons.

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Tunable magnons of an antiferromagnetic Mott insulator via interfacial metal-insulator transitions

Abstract

Bibliographical note

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