Sun, Qiyang; Hou, Songrui; Wei, Bin; Su, Yaokun; Ortiz, Victor; Sun, Bo; Lin, Jiao Y. Y.; Smith, Hillary; Danilkin, Sergey; Abernathy, Douglas L.; Wilson, Richard B.; Li, Chen
Spin-Phonon Interactions Induced Anomalous Thermal Conductivity in Nickel (II) Oxide Journal Article
In: Materials Today Physics, pp. 101094, 2023.
Abstract | Links | BibTeX | Tags: anharmonicity, DFT, lattice dynamics, magnon, magnon-phonon, neutron, oxide, phonon, thermal transport
@article{Sun2023,
title = {Spin-Phonon Interactions Induced Anomalous Thermal Conductivity in Nickel (II) Oxide},
author = {Qiyang Sun and Songrui Hou and Bin Wei and Yaokun Su and Victor Ortiz and Bo Sun and Jiao Y. Y. Lin and Hillary Smith and Sergey Danilkin and Douglas L. Abernathy and Richard B. Wilson and Chen Li},
url = {https://www.sciencedirect.com/science/article/abs/pii/S254252932300130X},
doi = {10.1016/j.mtphys.2023.101094},
year = {2023},
date = {2023-05-02},
urldate = {2023-05-02},
journal = {Materials Today Physics},
pages = {101094},
abstract = {Nickel (II) oxide is a prominent candidate for spintronic and spin-caloritronic applications operating at room temperature. Although there are extensive studies on nickel oxide, the roles of magnon- and spin-phonon interactions on thermal transport are not well understood. In the present work, the relationship between spin-phonon interactions and thermal transport is investigated by performing inelastic neutron scattering, time-domain thermoreflectance thermal conductivity measurements, and atomistic thermal transport calculations. Inelastic neutron scattering measurements of the magnon lifetime imply that magnon thermal conductivity is trivial, and so heat is conducted only by phonons. Time-domain thermoreflectance measurements of the thermal conductivity vs. temperature follow T-1.5 in the antiferromagnetic phase. This temperature dependence cannot be explained by phonon-isotope and phonon-defect scattering or phonon softening. Instead, we attribute this to magnon-phonon scattering and spin-induced dynamic symmetry breaking. The spin-phonon interactions are saturated in the paramagnetic phase and lead to a weaker temperature dependence of T-1.0 at 550-700 K. These results reveal the importance of spin-phonon interactions on lattice thermal transport, shedding light on the engineering of functional antiferromagnetic spintronic and spin-caloritronic materials through these interactions.},
keywords = {anharmonicity, DFT, lattice dynamics, magnon, magnon-phonon, neutron, oxide, phonon, thermal transport},
pubstate = {published},
tppubtype = {article}
}
Nickel (II) oxide is a prominent candidate for spintronic and spin-caloritronic applications operating at room temperature. Although there are extensive studies on nickel oxide, the roles of magnon- and spin-phonon interactions on thermal transport are not well understood. In the present work, the relationship between spin-phonon interactions and thermal transport is investigated by performing inelastic neutron scattering, time-domain thermoreflectance thermal conductivity measurements, and atomistic thermal transport calculations. Inelastic neutron scattering measurements of the magnon lifetime imply that magnon thermal conductivity is trivial, and so heat is conducted only by phonons. Time-domain thermoreflectance measurements of the thermal conductivity vs. temperature follow T-1.5 in the antiferromagnetic phase. This temperature dependence cannot be explained by phonon-isotope and phonon-defect scattering or phonon softening. Instead, we attribute this to magnon-phonon scattering and spin-induced dynamic symmetry breaking. The spin-phonon interactions are saturated in the paramagnetic phase and lead to a weaker temperature dependence of T-1.0 at 550-700 K. These results reveal the importance of spin-phonon interactions on lattice thermal transport, shedding light on the engineering of functional antiferromagnetic spintronic and spin-caloritronic materials through these interactions.
Cai, Qingan; Zhang, Yuemei; Luong, Diana; Tulk, Christopher A.; Fokwa, Boniface P. T.; Li, Chen
Spin–Phonon Interactions and Anharmonic Lattice Dynamics in Fe3GeTe2 Journal Article
In: Advanced Physics Research, no. 2200089, 2023.
Abstract | Links | BibTeX | Tags: anharmonicity, DFT, high pressure, magnon-phonon, Raman, selenide
@article{Cai2023,
title = {Spin\textendashPhonon Interactions and Anharmonic Lattice Dynamics in Fe3GeTe2},
author = {Qingan Cai and Yuemei Zhang and Diana Luong and Christopher A. Tulk and Boniface P.T. Fokwa and Chen Li},
url = {https://onlinelibrary.wiley.com/doi/10.1002/apxr.202200089},
doi = {10.1002/apxr.202200089},
year = {2023},
date = {2023-03-24},
urldate = {2023-03-24},
journal = {Advanced Physics Research},
number = {2200089},
abstract = {Raman scattering is performed on Fe3GeTe2 (FGT) at temperatures from 8 to 300 K and under pressures from the ambient pressure to 9.43 GPa. Temperature-dependent and pressure-dependent Raman spectra are reported. The results reveal respective anomalous softening and moderate stiffening of the two Raman active modes as a result of the increase of pressure. The anomalous softening suggests anharmonic phonon dynamics and strong spin\textendashphonon coupling. Pressure-dependent density functional theory and phonon calculations are conducted and used to study the magnetic properties of FGT and assign the observed Raman modes E^2_2g and A^1_1g. The calculations proved the strong spin\textendashphonon coupling for the E^2_2g mode. In addition, a synergistic interplay of pressure-induced reduction of spin exchange interactions and spin\textendashorbit coupling effect accounts for the softening of the E^2_2g mode as pressure increases.},
keywords = {anharmonicity, DFT, high pressure, magnon-phonon, Raman, selenide},
pubstate = {published},
tppubtype = {article}
}
Raman scattering is performed on Fe3GeTe2 (FGT) at temperatures from 8 to 300 K and under pressures from the ambient pressure to 9.43 GPa. Temperature-dependent and pressure-dependent Raman spectra are reported. The results reveal respective anomalous softening and moderate stiffening of the two Raman active modes as a result of the increase of pressure. The anomalous softening suggests anharmonic phonon dynamics and strong spin–phonon coupling. Pressure-dependent density functional theory and phonon calculations are conducted and used to study the magnetic properties of FGT and assign the observed Raman modes E^2_2g and A^1_1g. The calculations proved the strong spin–phonon coupling for the E^2_2g mode. In addition, a synergistic interplay of pressure-induced reduction of spin exchange interactions and spin–orbit coupling effect accounts for the softening of the E^2_2g mode as pressure increases.
Sun, Qiyang; Wei, Bin; Su, Yaokun; Smith, Hillary; Lin, Jiao Y. Y.; Abernathy, Douglas L.; Li, Chen
Mutual spin-phonon driving effects and phonon eigenvector renormalization in nickel (II) oxide Journal Article
In: Proceedings of the National Academy of Sciences, vol. 119, iss. 29, pp. e2120553119, 2022.
Abstract | Links | BibTeX | Tags: anharmonicity, antiferromagnetic, first-principles, magnon, magnon-phonon
@article{nokey,
title = {Mutual spin-phonon driving effects and phonon eigenvector renormalization in nickel (II) oxide},
author = {Qiyang Sun and Bin Wei and Yaokun Su and Hillary Smith and Jiao Y. Y. Lin and Douglas L. Abernathy and Chen Li},
url = {https://www.pnas.org/doi/10.1073/pnas.2120553119},
doi = {10.1073/pnas.2120553119},
year = {2022},
date = {2022-07-12},
urldate = {2022-07-12},
journal = {Proceedings of the National Academy of Sciences},
volume = {119},
issue = {29},
pages = {e2120553119},
abstract = {The physics of mutual interaction of phonon quasiparticles with electronic spin degrees of freedom, leading to unusual transport phenomena of spin and heat, has been a subject of continuing interests for decades. Despite its pivotal role in transport processes, the effect of spin-phonon coupling on the phonon system, especially acoustic phonon properties, has so far been elusive. By means of inelastic neutron scattering and first-principles calculations, anomalous scattering spectral intensity from acoustic phonons was identified in the exemplary collinear antiferromagnetic nickel (II) oxide, unveiling strong spin-lattice correlations that renormalize the polarization of acoustic phonon. In particular, a clear magnetic scattering signature of the measured neutron scattering intensity from acoustic phonons is demonstrated by its momentum transfer and temperature dependences. The anomalous scattering intensity is successfully modeled with a modified magneto-vibrational scattering cross-section, suggesting the presence of spin precession driven by phonon. The renormalization of phonon eigenvector is indicated by the observed “geometry-forbidden” neutron scattering intensity from transverse acoustic phonon. Importantly, the eigenvector renormalization cannot be explained by magnetostriction but instead, it could result from the coupling between phonon and local magnetization of ions.},
keywords = {anharmonicity, antiferromagnetic, first-principles, magnon, magnon-phonon},
pubstate = {published},
tppubtype = {article}
}
The physics of mutual interaction of phonon quasiparticles with electronic spin degrees of freedom, leading to unusual transport phenomena of spin and heat, has been a subject of continuing interests for decades. Despite its pivotal role in transport processes, the effect of spin-phonon coupling on the phonon system, especially acoustic phonon properties, has so far been elusive. By means of inelastic neutron scattering and first-principles calculations, anomalous scattering spectral intensity from acoustic phonons was identified in the exemplary collinear antiferromagnetic nickel (II) oxide, unveiling strong spin-lattice correlations that renormalize the polarization of acoustic phonon. In particular, a clear magnetic scattering signature of the measured neutron scattering intensity from acoustic phonons is demonstrated by its momentum transfer and temperature dependences. The anomalous scattering intensity is successfully modeled with a modified magneto-vibrational scattering cross-section, suggesting the presence of spin precession driven by phonon. The renormalization of phonon eigenvector is indicated by the observed “geometry-forbidden” neutron scattering intensity from transverse acoustic phonon. Importantly, the eigenvector renormalization cannot be explained by magnetostriction but instead, it could result from the coupling between phonon and local magnetization of ions.
Su, Yaokun; Smith, Hillary L.; Stone, Matthew B.; Abernathy, Douglas L.; Lumsden, Mark D.; Adams, Carl P.; Li, Chen
Frustration-induced diffusive scattering anomaly and dimension change in FeGe2 Journal Article
In: Physical Review B, vol. 106, no. 024406, 2022.
Abstract | Links | BibTeX | Tags: frustration, magnetism, magnon-phonon, neutron, neutron scattering, phonon
@article{nokey,
title = {Frustration-induced diffusive scattering anomaly and dimension change in FeGe2},
author = {Yaokun Su and Hillary L. Smith and Matthew B. Stone and Douglas L. Abernathy and Mark D. Lumsden and Carl P. Adams and Chen Li},
url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.106.024406},
doi = {10.1103/PhysRevB.106.024406},
year = {2022},
date = {2022-07-11},
urldate = {2022-07-11},
journal = {Physical Review B},
volume = {106},
number = {024406},
abstract = {Magnetic frustration, arising from the competition of exchange interactions, has received great attention because of its relevance to exotic quantum phenomena in materials. In the current work, we report an unusual checkerboard-shaped scattering anomaly in FeGe2, far from the known incommensurate magnetic satellite peaks, by inelastic neutron scattering. More surprisingly, such phenomenon appears as spin dynamics at low temperature, but it becomes prominent above N\'{e}el transition as elastic scattering. A model Hamiltonian that includes an intraplane next-nearest neighbor was proposed and such anomaly is attributed to the near-perfect magnetic frustration and the emergence of unexpected two-dimensional magnetic order in the quasi-one-dimensional FeGe2.},
keywords = {frustration, magnetism, magnon-phonon, neutron, neutron scattering, phonon},
pubstate = {published},
tppubtype = {article}
}
Magnetic frustration, arising from the competition of exchange interactions, has received great attention because of its relevance to exotic quantum phenomena in materials. In the current work, we report an unusual checkerboard-shaped scattering anomaly in FeGe2, far from the known incommensurate magnetic satellite peaks, by inelastic neutron scattering. More surprisingly, such phenomenon appears as spin dynamics at low temperature, but it becomes prominent above Néel transition as elastic scattering. A model Hamiltonian that includes an intraplane next-nearest neighbor was proposed and such anomaly is attributed to the near-perfect magnetic frustration and the emergence of unexpected two-dimensional magnetic order in the quasi-one-dimensional FeGe2.
Li, Junxue; Simensen, Haakon T.; Reitz, Derek; Sun, Qiyang; Yuan, Wei; Li, Chen; Tserkovnyak, Yaroslav; Brataas, Arne; Shi, Jing
Observation of Magnon Polarons in a Uniaxial Antiferromagnetic Insulator Journal Article
In: Phys. Rev. Lett. , vol. 125, pp. 217201, 2020.
Abstract | Links | BibTeX | Tags: antiferromagnetic, magnon, magnon-phonon, polaron
@article{Li2020b,
title = {Observation of Magnon Polarons in a Uniaxial Antiferromagnetic Insulator},
author = {Junxue Li and Haakon T. Simensen and Derek Reitz and Qiyang Sun and Wei Yuan and Chen Li and Yaroslav Tserkovnyak and Arne Brataas and Jing Shi},
url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.217201},
doi = {10.1103/PhysRevLett.125.217201},
year = {2020},
date = {2020-11-17},
journal = {Phys. Rev. Lett. },
volume = {125},
pages = {217201},
abstract = {Magnon polarons, a type of hybridized excitations between magnons and phonons, were first reported in yttrium iron garnet as anomalies in the spin Seebeck effect responses. Here, we report an observation of antiferromagnetic (AFM) magnon polarons in a uniaxial AFM insulator Cr2O3. Despite the relatively higher energy of magnon than that of the acoustic phonons, near the spin-flop transition of ∼6T, the left-handed magnon spectrum shifts downward to hybridize with the acoustic phonons to form AFM magnon polarons, which can also be probed by the spin Seebeck effect. The spin Seebeck signal is founded to be enhanced due to the magnon polarons at low temperatures.},
keywords = {antiferromagnetic, magnon, magnon-phonon, polaron},
pubstate = {published},
tppubtype = {article}
}
Magnon polarons, a type of hybridized excitations between magnons and phonons, were first reported in yttrium iron garnet as anomalies in the spin Seebeck effect responses. Here, we report an observation of antiferromagnetic (AFM) magnon polarons in a uniaxial AFM insulator Cr2O3. Despite the relatively higher energy of magnon than that of the acoustic phonons, near the spin-flop transition of ∼6T, the left-handed magnon spectrum shifts downward to hybridize with the acoustic phonons to form AFM magnon polarons, which can also be probed by the spin Seebeck effect. The spin Seebeck signal is founded to be enhanced due to the magnon polarons at low temperatures.