A crystal-field route to THz-driven magnetization

A. Kirilyuk; A.V. Boris; C.S. Davies; M.S. Mrudul; M. Weissenhofer; P.M. Oppeneer; T. Zalewski; Y. Lee

REVIEW 2 major objections 4 minor 39 references

Resonant crystal-field transitions turn circular THz light into magnetization that flips sign across the resonance.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

T0 review · grok-4.5

2026-07-10 06:03 UTC pith:XK5GJ43O

load-bearing objection Clean wavelength-dependent sign reversal of THz-driven magnetization in CeF3 that tracks crystal-field resonances and a parameter-light electronic IFE model, not the phonon spectrum. the 2 major comments →

arxiv 2607.08519 v1 pith:XK5GJ43O submitted 2026-07-09 cond-mat.mtrl-sci cond-mat.other

A crystal-field route to THz-driven magnetization

T. Zalewski , M.S. Mrudul , Y. Lee , M. Weissenhofer , A.V. Boris , P.M. Oppeneer , A. Kirilyuk , C.S. Davies This is my paper

classification cond-mat.mtrl-sci cond-mat.other

keywords crystal-field excitationsinverse Faraday effectTHz magnetizationCeF3helicity-dependent Faraday rotationrare-earth 4f statesultrafast magnetism

verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

Light carries angular momentum, but the microscopic routes that convert it into magnetic order are still being mapped. This paper shows that the crystal-field levels of localized rare-earth 4f electrons—normally treated as static spectroscopic labels—can act as an active reservoir that absorbs optical angular momentum and produces net magnetization. In the paramagnet CeF3, circularly polarized THz pulses tuned to the lowest Ce3+ crystal-field resonance generate a helicity-dependent magnetization that lasts up to ~100 ps. Holding helicity fixed and simply detuning the wavelength across the resonance reverses the magnetization sign, producing a dispersive spectrum that tracks the electronic crystal-field lines rather than the optical phonons. A quantum inverse-Faraday calculation based only on the known crystal-field states reproduces both the resonance positions and the sign flip. The result expands the set of microscopic pathways available for THz control of magnetism and points to crystal-field engineering as a design handle.

Core claim

Resonant excitation of localized 4f crystal-field transitions in CeF3 converts the angular momentum of circularly polarized THz light into a long-lived helicity-dependent magnetization whose spectral response is dispersive and reverses sign across the crystal-field resonance, matching resonant electronic inverse-Faraday theory rather than the phonon absorption spectrum.

What carries the argument

Resonant electronic inverse Faraday effect on crystal-field Kramers doublets: circularly polarized light preferentially drives one member of a doublet over its partner, creating a nonequilibrium population imbalance that yields net magnetization; detuning through resonance reverses the imbalance and therefore the magnetization sign.

Load-bearing premise

The clean dispersive magneto-optical feature near 71–88 μm is treated as essentially pure electronic crystal-field response, with phonon or vibronic hybridization assumed negligible in that window.

What would settle it

A high-resolution measurement or calculation showing that the magneto-optical spectrum tracks a Raman- or infrared-active phonon mode (or a vibronic hybrid) rather than the isolated crystal-field transition would collapse the pure crystal-field claim.

Watch this falsifier — get emailed when new claim-graph text bears on it.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Desk Editor's Note

Clean wavelength-dependent sign reversal of THz-driven magnetization in CeF3 that tracks crystal-field resonances and a parameter-light electronic IFE model, not the phonon spectrum.

read the letter

The real news here is the dispersive Faraday spectrum: with helicity fixed, the induced magnetization flips sign as they tune across the ~71 μm Ce3+ crystal-field resonance, and a pure electronic inverse-Faraday calculation using fixed 1980 wavefunctions and energies reproduces that flip. That is new relative to the 2023 Luo et al. phonon claim on the same material, and the data package is solid enough to force the community to re-weight electronic versus phononic channels.

What they do well: helicity-odd Faraday traces, exact inversion on helicity flip, null for linear polarization, linear fluence dependence, and a direct overlay of the magneto-optical spectrum against ellipsometric ε2. The strongest response sits where phonon absorption is weak; several strong Eu phonons produce almost nothing. The theory is not a free fit—crystal-field parameters are taken from Ahrens/Gerlinger & Schaack, only a single linewidth and the experimental peak field are set, and the dominant KdA term already gives the observed dispersive shape. Lifetime ~100 ps is consistent with a long-lived population imbalance after the coherent drive is gone.

Soft spots are real but secondary. Near 34 μm the spectrum is vibronically mixed, so assignment is ambiguous; the paper says so. An ENZ region near 92 μm may reshape the local field and could contribute to the slower rise at 88 μm. Data are not yet public. None of these overturn the clean 70–90 μm window that carries the central claim.

This is for people working on ultrafast magnetism, rare-earth THz control, and the phonon-versus-electronic angular-momentum debate. It deserves a serious referee and will be cited. I would bring it to reading group and would accept it for peer review without hesitation.

Referee Report

2 major / 4 minor

Summary. The manuscript reports that resonant excitation of localized Ce3+ 4f crystal-field transitions in paramagnetic CeF3 by circularly polarized THz pulses generates a helicity-dependent magnetization lasting ~100 ps. Wavelength-selective ultrafast Faraday spectroscopy shows a dispersive magneto-optical spectrum that reverses sign across the lowest crystal-field resonance (~71 μm) even at fixed helicity, tracks the crystal-field spectrum rather than the infrared-active Eu phonon spectrum, and is reproduced by a resonant electronic inverse-Faraday calculation that uses fixed literature crystal-field energies and wavefunctions. Linear-polarization null controls, helicity inversion, and linear fluence dependence support an angular-momentum-transfer origin.

Significance. If correct, the work identifies crystal-field excitations as a previously under-appreciated dynamical reservoir that converts optical angular momentum into magnetization, complementing the recent emphasis on circularly polarized phonons. The combination of a clean spectral window (70–90 μm), parameter-fixed IFE theory that captures the sign reversal, and multiple experimental controls makes the claim falsifiable and of clear interest to ultrafast magnetism and THz control of quantum materials. The use of literature crystal-field parameters without refitting to the Faraday data is a notable strength.

major comments (2)

The central claim rests on the 70–90 μm dispersive feature being dominated by the pure electronic g± → e1∓ transition. The manuscript already notes possible hybridization with a Raman-active mode near 95 μm and an epsilon-near-zero region near 92 μm that can reshape the local field (main text and Supplementary Materials). A quantitative estimate of residual vibronic/ENZ weight in this window (e.g., comparison of oscillator strengths or a simple two-oscillator model) would strengthen the assertion that the electronic channel is primary rather than co-dominant.
The quantum IFE calculation (Supplementary Eqs. S1–S3, Fig. 3B) reproduces the sign-reversal shape with fixed literature crystal-field parameters and a single phenomenological linewidth Γ = 2.5 meV. The absolute magnetization scale (~0.25 μB/Ce) depends on both Γ and the assumed peak field (0.13 MV/cm). A short sensitivity analysis or explicit comparison of the calculated absolute Faraday rotation with the calibrated experimental value (~40 mdeg ≈ 10 T equivalent) would make the quantitative agreement more transparent.

minor comments (4)

Fig. 2A and the corresponding text should state the fixed pump–probe delay used for the spectral scan and confirm that the delay remains near the peak for all wavelengths (or show that the spectral shape is robust to small delay variations).
The silicon phase-retarder characterization (Fig. S2) is shown only at 33 μm; a brief statement that the ellipticity remains comparable across 20–120 μm would reassure readers that helicity is truly fixed while scanning wavelength.
Clarify whether the Faraday calibration used for the ~10 T equivalent field is temperature- and wavelength-independent, or cite the relevant prior work more explicitly.
A few typographical inconsistencies appear (e.g., 3 4 μm vs 34 μm, occasional spacing around μm). These are easily corrected.

Circularity Check

0 steps flagged

No significant circularity: CF energies/wavefunctions fixed from 1980 spectroscopy; resonant IFE shape (incl. sign reversal) is a parameter-free prediction of the denominators, not a fit to the Faraday data.

full rationale

The load-bearing claim is that the observed helicity-odd, dispersive Faraday spectrum (sign flip across ~71–88 μm while helicity is held fixed) tracks the known Ce3+ crystal-field resonances rather than the Eu phonon spectrum, and is reproduced by the resonant electronic inverse-Faraday calculation. Crystal-field energies and |mJ> admixtures are taken verbatim from independent 1980 literature (Ahrens; Gerlinger & Schaack) and are never adjusted to the present magneto-optical data (Supp. Table 2). The IFE coefficients are the published Battiato–Oppeneer density-matrix expressions (Eqs. S1–S3); only a constant phenomenological linewidth (2.5 meV) and the experimental peak field (0.13 MV/cm) are inserted. The dispersive sign reversal itself arises directly from the resonant energy denominators and the unequal |r±| matrix elements between time-reversed Kramers components; it is therefore a genuine prediction of the fixed electronic structure, not a fitted or self-definitional construct. Magnitude scaling and minor self-citation of the IFE formalism are ordinary and non-load-bearing. Residual vibronic/ENZ caveats noted by the authors themselves affect only the secondary ~34 μm window and do not close a circular loop around the primary claim. The derivation chain is therefore self-contained against external spectroscopic benchmarks.

Axiom & Free-Parameter Ledger

2 free parameters · 3 axioms · 0 invented entities

Central claim rests on (i) literature crystal-field eigenstates treated as fixed inputs, (ii) the second-order density-matrix IFE formulas of Battiato et al., and (iii) two numerical parameters (linewidth, peak field) set to experimental estimates. No new particles or forces are postulated; the ‘dynamical reservoir’ language is interpretive, not ontological.

free parameters (2)

crystal-field linewidth Γ = 2.5 meV
Phenomenological dephasing set to 2.5 meV; controls resonance width and peak height of calculated M_IFE but not the existence of the sign reversal.
THz peak electric field = 0.13 MV/cm
Set to 0.13 MV/cm to match experimental fluence estimate; scales overall magnetization amplitude but not spectral shape.

axioms (3)

domain assumption Ce3+ 4f1 ground multiplet is split by the crystal field into three Kramers doublets whose energies and |mJ> compositions are those tabulated by Ahrens (1980) and Gerlinger & Schaack (1986).
Taken as fixed spectroscopic input; never re-fitted to the Faraday data.
domain assumption Induced magnetization is given by the second-order density-matrix inverse Faraday expressions of Battiato, Barbalinardo & Oppeneer (Phys. Rev. B 89, 014413, 2014).
Standard coherent IFE theory applied to the crystal-field manifold.
standard math Electric-dipole selection rules for circular light between crystal-field states follow the Wigner–Eckart theorem with Hartree–Fock radial integrals.
Used to evaluate the r± matrix elements that generate the population imbalance.

pith-pipeline@v1.1.0-grok45 · 21076 in / 2614 out tokens · 29092 ms · 2026-07-10T06:03:15.958743+00:00 · methodology

0 comments

read the original abstract

Light carries angular momentum, but the microscopic pathways that transform it into magnetization remain elusive. Here we establish that crystal-field excitations, historically viewed primarily as equilibrium spectroscopic fingerprints of localized 4$f$ electrons, constitute an active microscopic route through which circularly-polarized terahertz (THz) light creates magnetic polarization. Using wavelength-selective ultrafast Faraday spectroscopy on the paramagnetic insulator CeF$_3$, we show that resonant excitation of localized 4$f$ crystal-field transitions generates a helicity-dependent magnetization that survives for up to about 100 ps. Most strikingly, while the optical helicity is held fixed, the THz-driven response reverses sign as the excitation wavelength is tuned across the crystal-field resonance. The resulting dispersive spectral response follows the crystal-field excitation spectrum rather than that of optical phonons, and is captured by resonant electronic theory of the inverse Faraday effect. Our results identify crystal-field excitations as a previously unrecognized dynamical reservoir for optical angular momentum and broaden the microscopic pathways through which THz light can create and manipulate magnetic states.

discussion (0)

Reference graph

Works this paper leans on

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The crystal was double-side polished with a (001) crystal orientation, such that the crystallographic c- axis (optical axis) was normal to the surface

Materials Single-crystalline CeF3 (5 × 5 × 0.5 mm3) was purchased commercially from MSE Supplies. The crystal was double-side polished with a (001) crystal orientation, such that the crystallographic c- axis (optical axis) was normal to the surface. Measurements were also repeated on thicker crystals of CeF3, with thickness 2 mm, purchased commercially fr...

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FEL-1 provides wavelength-tunable radiation in the spectral range 25 -120 μm with an experimentally adjustable bandwidth of 0.35 -5%

Two-color pump-probe setup Far-infrared pump pulses were generated using the FEL -1 beamline of the free-electron lasers at HFML-FELIX (Nijmegen, The Netherlands) [S1]. FEL-1 provides wavelength-tunable radiation in the spectral range 25 -120 μm with an experimentally adjustable bandwidth of 0.35 -5%. The spectral distribution of the infrared pulses was m...

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Spectroscopic ellipsometry The low -temperature optical response of CeF₃ (measured at 1 2 K) was determined using synchrotron-based spectroscopic ellipsometry [S5]. Measurements in the frequency range 60 to 700 cm -1 (14-167 μm) were performed using homemade ellipsometers in combination with a Bruker IFS 66v/S Fourier -transform infrared spectrometer. To ...

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Crystal field energies and wavefunctions of cerium trifluoride The crystal-field level scheme of CeF3 has been studied for more than half a century. These studies consistently show that the Ce 3+ ion, with a single 4 f electron, possesses a 2 F5/2 ground-state multiplet that is split by the crystal field of the fluorine ions into three Kramers doublets [S...

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[35]

Quantum inverse Faraday model A quantum -mechanical description of the inverse Faraday effect based on density -matrix perturbation theory, second order in the electric field, was developed in Ref. [S9]. It has been previously applied to calculate the coherent laser -induced magnetization in metals [S10]-[S11]. The induced magnetization can be written as ...

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[36]

Discussion of dependences for fixed sample temperature, and method of fitting In the pump-probe measurements, we additionally studied how the measured signals depend on the energy of the THz excitation . In Fig. S6A-B, we show time -resolved traces obtained with circularly polarized pump pulses centered at 7 4 and 88 μm, respectively. To quantify how the ...

work page
[37]

Phononic and vibronic excitations in cerium trifluoride The low-energy excitation spectrum of CeF3 has been extensively investigated using Raman [S9], infrared [S6], and neutron spectroscopy [S14]. A central finding of these studies is that the crystal- field excitations of the Ce 3+ 4f manifold are strongly coupled to lattice vibrations, giving rise to p...

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[38]

[S4], Fig

Spectral comparison of magnetization and infrared-active phonons near 30 μm To further examine the microscopic origin of the helicity-dependent magnetization in the spectral region previously associated with circularly polarized phonons in Ref. [S4], Fig. S8 shows a magnified comparison between the measured magneto-optical response and the imaginary part ...

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Inelastic Neutron Scattering for Direct Detection of Chiral Phonons

Physical mechanism of the light-induced magnetization We present the separate contributions of the 𝐾𝑜,𝑧, 𝐾𝑑𝐴,𝑧, and 𝐾𝑑𝐵,𝑧 terms [defined in Eqs. (S1)- (S3)] to the light -induced magnetization in Fig. S9. The results clearly show that the experimentally observed features are well explained by the 𝐾𝑑𝐴,𝑧 term. Under appropriate assumptions, Eq. (S2) can be ...

work page internal anchor Pith review Pith/arXiv arXiv 1998

[1] [1]

L. P. Pitaevskii, Electric forces in a transparent dispersive medium. Sov. Phys. JETP 12, 1008 (1961)

work page 1961

[2] [2]

Beaurepaire, J

E. Beaurepaire, J. -C. Merle, A. Daunois, and J. -Y . Bigot, Ultrafast spin dynamics in ferromagnetic nickel. Phys. Rev. Lett. 76, 4250 (1996)

work page 1996

[3] [3]

A. V. Kimel, A. Kirilyuk, P. A. Usachev, R. V. Pisarev, A. M. Balbashov, and Th. Rasing, Ultrafast non-thermal control of magnetization by instantaneous photomagnetic pulses . Nature 435, 655 (2005). 8

work page 2005

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Dornes et al., The ultrafast Einstein–de Haas effect

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S. R. Tauchert et al., Polarized phonons carry angular momentum in ultrafast demagnetization. Nature 602, 73 (2022)

work page 2022

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J. Luo, T. Lin, J. Zhang, X. Chen, E. R. Blackert, R. Xu, B. I. Yakobson, and H. Zhu, Large effective magnetic fields from chiral phonons in rare-earth halides. Science 382, 698 (2023)

work page 2023

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Basini, M

M. Basini, M. Pancaldi, B. Wehinger, M. Udina, V. Unikandanunni, T. Tadano, M. C. Hoffmann, A. V. Balatsky, and S. Bonetti, Terahertz electric -field-driven dynamical multiferroicity in SrTiO3. Nature 628, 534 (2024)

work page 2024

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C. S. Davies, F. G. N. Fennema, A. Tsukamoto, I. Razdolski, A. V. Kimel, and A. Kirilyuk, Phononic switching of magnetization by the ultrafast Barnett effect . Nature 628, 540 (2024)

work page 2024

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Shabala, F

N. Shabala, F. Tietjen, and R. M. Geilhufe, Axial phono -magnetic effects . arXiv:2511.03329 (2025)

work page arXiv 2025

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Gerlinger and G

H. Gerlinger and G. Schaack, Crystal-field states of the Ce 3+ ion in CeF3: A demonstration of vibronic interaction in ionic rare-earth compounds. Phys. Rev. B 33, 7438 (1986)

work page 1986

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R. P. Bauman and S. P. S. Porto, Lattice Vibrations and Structure of Rare-Earth Fluorides. Phys. Rev. 161, 842 (1967)

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Ahrens, Optical phonons in CecLa1-cF3 single crystals

K. Ahrens, Optical phonons in CecLa1-cF3 single crystals. Z. Phys. B – Cond. Matt. 40, 45 (1980)

work page 1980

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G. M. H. Knippels and A. F. G. van der Meer, FEL diagnostics and user control. Nucl. Instrum. Methods Phys. Res. 144, 32 (1998)

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T. N. Stanislavchuk et al., Synchrotron radiation -based far -infrared spectroscopic ellipsometer with full Mueller-matrix capability. Rev. Sci. Instrum. 84, 023901 (2013)

work page 2013

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Berritta, R

M. Berritta, R. Mondal, K. Carva, and P. M. Oppeneer, Ab initio theory of coherent laser- induced magnetization in metals. Phys. Rev. Lett. 117, 137203 (2016)

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Merlin, Unraveling the effect of circularly polarized light on reciprocal media: Breaking time reversal symmetry with non -Maxwellian magnetic-esque fields

R. Merlin, Unraveling the effect of circularly polarized light on reciprocal media: Breaking time reversal symmetry with non -Maxwellian magnetic-esque fields. Phys. Rev. B 110, 094312 (2024). 9

work page 2024

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T. I. Larkin, R. D. Dawson, M. Höppner, T. Takayama, M. Isobe, Y .-L. Mathis, H. Takagi, B. Keimer, and A. V. Boris, Infrared phonon spectra of quasi -one-dimensional Ta2NiSe5 and Ta2NiS5. Phys. Rev. B 98, 125113 (2018)

work page 2018

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R. P. Lowndes, J. F. Parish, and C. H. Perry, Optical phonons and symmetry of tysonite lanthanide fluorides. Phys. Rev. 182, 913 (1969)

work page 1969

[21] [21]

D. M. Juraschek, T. Neuman, and P. Narang, Giant effective magnetic fields from optically driven chiral phonons in 4𝑓 paramagnets. Phys. Rev. Res. 4, 013129 (2022)

work page 2022

[22] [22]

Chaudhary, D

S. Chaudhary, D . M. Juraschek, M . Rodriguez-Vega, and G. A. Fiete, Giant effective magnetic moments of chiral phonons from orbit-lattice coupling. Phys. Rev. B 110, 094401 (2024)

work page 2024

[23] [23]

Merlin, Magnetophononics and the chiral phonon misnomer

R. Merlin, Magnetophononics and the chiral phonon misnomer . PNAS Nexus 4, pgaf002 (2025)

work page 2025

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Light-induced Faraday effect from dynamical breakdown of Kleinman symmetry

N. Sellati, J. Fiore, and L. Benfatto, Light -induced Faraday effect from dynamical breakdown of Kleinman symmetry. arXiv 2605.27127 (2026)

work page internal anchor Pith review Pith/arXiv arXiv 2026

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J. P. van der Ziel, P. S. Pershan, and L. D. Malmstrom, Optically-induced magnetization resulting from the inverse Faraday effect. Phys. Rev. Lett. 15, 190 (1965)

work page 1965

[26] [26]

Battiato, G

M. Battiato, G. Barbalinardo, and P. M. Oppeneer, Quantum theory of the inverse Faraday effect. Phys. Rev. B 89, 014413 (2014)

work page 2014

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A. V. Savinkov, S. L. Korableva, M. S. Tagirov, H. Suzuki, K. Matsumoto, and S. Abe, Revised measurements and interpretation of magnetic properties of oriented CeF3 single crystals. J. Low Temp. Phys. 185, 603 (2016)

work page 2016

[28] [28]

Reshef, I

O. Reshef, I. De Leon, M. Z. Alam, and R. W. Boyd, Nonlinear optical effects in epsilon- near-zero media. Nat Rev Mater 4, 535 (2019)

work page 2019

[29] [29]

Kinsey, C

N. Kinsey, C. DeVault, A. Boltasseva, and V . M. Shalaev, Near-zero-index materials for photonics. Nat. Rev. Mater. 4, 742 (2019)

work page 2019

[30] [30]

Kwaaitaal, D

M. Kwaaitaal, D. G. Lourens, C. S. Davies, and A. Kirilyuk, Epsilon -near-zero regime enables permanent ultrafast all -optical reversal of ferroelectric polarization. Nat. Photon . 18, 569 (2024). ACKNOWLEDGEMENTS We thank all technical staff at FELIX for their technical support , Nils Des smann and Dmytro Afanasiev for fruitful discussions, and Y.-L. Mat...

work page arXiv 2024

[31] [31]

The crystal was double-side polished with a (001) crystal orientation, such that the crystallographic c- axis (optical axis) was normal to the surface

Materials Single-crystalline CeF3 (5 × 5 × 0.5 mm3) was purchased commercially from MSE Supplies. The crystal was double-side polished with a (001) crystal orientation, such that the crystallographic c- axis (optical axis) was normal to the surface. Measurements were also repeated on thicker crystals of CeF3, with thickness 2 mm, purchased commercially fr...

work page

[32] [32]

FEL-1 provides wavelength-tunable radiation in the spectral range 25 -120 μm with an experimentally adjustable bandwidth of 0.35 -5%

Two-color pump-probe setup Far-infrared pump pulses were generated using the FEL -1 beamline of the free-electron lasers at HFML-FELIX (Nijmegen, The Netherlands) [S1]. FEL-1 provides wavelength-tunable radiation in the spectral range 25 -120 μm with an experimentally adjustable bandwidth of 0.35 -5%. The spectral distribution of the infrared pulses was m...

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[33] [33]

Spectroscopic ellipsometry The low -temperature optical response of CeF₃ (measured at 1 2 K) was determined using synchrotron-based spectroscopic ellipsometry [S5]. Measurements in the frequency range 60 to 700 cm -1 (14-167 μm) were performed using homemade ellipsometers in combination with a Bruker IFS 66v/S Fourier -transform infrared spectrometer. To ...

work page

[34] [34]

Crystal field energies and wavefunctions of cerium trifluoride The crystal-field level scheme of CeF3 has been studied for more than half a century. These studies consistently show that the Ce 3+ ion, with a single 4 f electron, possesses a 2 F5/2 ground-state multiplet that is split by the crystal field of the fluorine ions into three Kramers doublets [S...

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[35] [35]

Quantum inverse Faraday model A quantum -mechanical description of the inverse Faraday effect based on density -matrix perturbation theory, second order in the electric field, was developed in Ref. [S9]. It has been previously applied to calculate the coherent laser -induced magnetization in metals [S10]-[S11]. The induced magnetization can be written as ...

work page

[36] [36]

Discussion of dependences for fixed sample temperature, and method of fitting In the pump-probe measurements, we additionally studied how the measured signals depend on the energy of the THz excitation . In Fig. S6A-B, we show time -resolved traces obtained with circularly polarized pump pulses centered at 7 4 and 88 μm, respectively. To quantify how the ...

work page

[37] [37]

Phononic and vibronic excitations in cerium trifluoride The low-energy excitation spectrum of CeF3 has been extensively investigated using Raman [S9], infrared [S6], and neutron spectroscopy [S14]. A central finding of these studies is that the crystal- field excitations of the Ce 3+ 4f manifold are strongly coupled to lattice vibrations, giving rise to p...

work page

[38] [38]

[S4], Fig

Spectral comparison of magnetization and infrared-active phonons near 30 μm To further examine the microscopic origin of the helicity-dependent magnetization in the spectral region previously associated with circularly polarized phonons in Ref. [S4], Fig. S8 shows a magnified comparison between the measured magneto-optical response and the imaginary part ...

work page

[39] [39]

Inelastic Neutron Scattering for Direct Detection of Chiral Phonons

Physical mechanism of the light-induced magnetization We present the separate contributions of the 𝐾𝑜,𝑧, 𝐾𝑑𝐴,𝑧, and 𝐾𝑑𝐵,𝑧 terms [defined in Eqs. (S1)- (S3)] to the light -induced magnetization in Fig. S9. The results clearly show that the experimentally observed features are well explained by the 𝐾𝑑𝐴,𝑧 term. Under appropriate assumptions, Eq. (S2) can be ...

work page internal anchor Pith review Pith/arXiv arXiv 1998