Structural Phase Transition in Antiferromagnet CeCoSi Compared to Isostructural LaCoSi and PrCoSi

Kawamura, Yukihiro; Tanida, Hiroshi; Ueda, R.; Hoshino, Junichi; Takeda, Keiki; Sekine, Chihiro

doi:10.7566/jpsj.89.054702

Cited by 11 publications

(13 citation statements)

References 25 publications

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“…The XRD patterns at 70 K and 30 K show that the sample is in Phase IV. 15) At an intermediate temperature of 90 K in Fig. 1(b), the XRD pattern consists of the 200 peak observed at 250 K and the single peak observed at 70 K. Similar behaviors can be seen at 2θ ∼ 25.5 • .…”

Section: Xrd Near the I-iv Phase Boundarysupporting

confidence: 58%

“…This is consistent with our previous report; the XRD pattern at P s ∼ 4.9 GPa at 300 K indicates the coexistence of the two phases. 15) All of the XRD patterns can be classified into Phase I, Phase IV, and the coexistent state of Phases I and IV (Phase I+IV) in the same manner as the XRD patterns in Fig. 1(a).…”

Section: Xrd Near the I-iv Phase Boundarymentioning

confidence: 99%

“…Another intriguing feature of this compound is a structural phase transition induced by pressure at P s ∼ 4.9 GPa at 300 K from the low-pressure phase (Phase I) with the tetragonal P4/nmm structure to a high-pressure phase (Phase IV), which is possibly orthorhombic. 15) One of the key factors for this structural transition is proposed to be a decrease in the ratio of the tetragonal lattice constants c/a. The c/a of CeCoSi decreases continuously under pressure, which is not observed in the c/a of its isostructural counterparts LaCoSi and PrCoSi, suggesting that Ce-4 f electrons play an essential role for the structural transition at P s .…”

Section: Introductionmentioning

confidence: 99%

“…The c/a threshold at P s for CeCoSi is ∼1.69. 15) The RCoSi (R = rare earth) also changes its crystal structure by the lanthanoid contraction; from LaCoSi to TbCoSi the structure is CeFeSi-type, whereas from DyCoSi to LuCoSi the structure changes to an orthorhombic TiNiSitype. 16,17) The fact that the c/a of TbCoSi is ∼1.69 implies that the c/a threshold for the structural change in RCoSi is ∼1.69 and that the structure can be changed either by applying a pressure or replacing the R ion.…”

Section: Introductionmentioning

confidence: 99%

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Structural Phase Transition and Possible Valence Instability of Ce$-4f$ Electron Induced by Pressure in CeCoSi

Kawamura,

Ikeda,

Dalan

et al. 2022

Preprint

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X-ray powder diffraction and electrical resistivity measurements were performed on the tetragonal compound CeCoSi under pressure to elucidate the phase boundary of the pressure-induced structural transition and the change in the 4 f electronic state. The temperature-pressure phase diagram has been determined from the shift of the Bragg peaks and from the anomaly in the resistivity. The critical pressure, P s ∼ 4.9 GPa at 300 K, decreases to P s ∼ 3.6 GPa at 10 K. The decrease of P s is due not only to the decrease in volume of the unit cell but also to an anisotropic shrinkage by cooling. When crossing the boundary to the high-pressure phase, the resistivity shows a significant drop to exhibit a metallic temperature dependence. The results of this study strongly suggest that the structural phase transition can be ascribed to valence instability of Ce-4 f electron.

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Section: Xrd Near the I-iv Phase Boundarysupporting

confidence: 58%

Section: Xrd Near the I-iv Phase Boundarymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structural Phase Transition and Possible Valence Instability of Ce$-4f$ Electron Induced by Pressure in CeCoSi

Kawamura,

Ikeda,

Dalan

et al. 2022

Preprint

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“…In the present study, we propose that the NQR and NMR can be another good probe to detect cluster odd-parity multipoles. To demonstrate that, we analyze the NQR and NMR spectra under the odd-parity multipole orderings by considering the candidate, CeCoSi, which may host two types of oddparity multipole orders depending on temperature and pressure [51][52][53][54][55][56][57][58]. The crystal structure of CeCoSi is the centrosymmetric CeFeSi-type structure (P4/nmm, D 7 4h , No.…”

Section: Introductionmentioning

confidence: 99%

NQR and NMR spectra in the odd-parity multipole material CeCoSi

Yatsushiro

Hayami

2020

Phys. Rev. B

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We theoretically study NQR and NMR spectra in the presence of odd-parity multipoles originating from staggered antiferromagnetic and antiferroquadrupole orderings. For the f-electron metal, CeCoSi, which is a candidate hosting odd-parity multipoles, we derive an effective hyperfine field acting on Co nucleus generated from electronic origin multipole moments at Ce ion under zero and nonzero magnetic fields. We elucidate that emergent odd-parity multipoles give rise to sublattice-dependent spectral splittings in NQR and NMR through the effective hyperfine coupling in the absence of the global inversion symmetry. We mainly examine behaviors of the NQR and NMR spectra in three odd-parity multipole ordered states: a y-type magnetic toroidal dipole order with a staggered x-type antiferromagnetic structure, an xy-type electric toroidal quadrupole order with a staggered x 2 − y 2-type antiferroquadrupole structure, and a z-type electric dipole order with a staggered 3z 2 − r 2type antiferroquadrupole structure. We show that different odd-parity multipole orders lead to different fielddependent spectral splittings in NMR, while only the xy-type electric toroidal quadrupole order exhibits the NQR spectral splitting. We also present possible sublattice-dependent spectral splittings for all the odd-parity multipole orders potentially activated in low-energy crystal-field levels, which will be useful to identify oddparity order parameters in CeCoSi by NQR and NMR measurements.

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Semimetallic Orbital Hybridization by Particular Surface Engineering in Ternary Cobalt Silicide to Accelerate Oxygen Evolution Reaction

Shan

Sun

Wang

et al. 2023

Physica Rapid Research Ltrs

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The oxygen evolution reaction (OER) plays an important role in efficient energy conversion, but needs excellent catalysts to overcome the sluggish reaction kinetics. The classic reaction kinetics implies that catalytic activity strongly depends on the electronic‐state occupation at surface active sites. Herein, a semimetallic orbital‐hybridization strategy is suggested to optimize the reaction activity of metal site at ternary cobalt silicide surface by particular interlayer electronic‐state coupling, which is completely different from the atomic configuration with double‐layered metal surface. The detailed analysis about electronic structure demonstrates that the semimetallic orbital hybridization is responsible for reducing OER activation barrier, due to a proper bonding strength. Instead, the stronger metallization cannot benefit a fast intermediate dissociation, which requires a higher activation barrier at OER. Herein, a new insight into accelerating OER by a particular surface engineering is provided.

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Structural Phase Transition in Antiferromagnet CeCoSi Compared to Isostructural LaCoSi and PrCoSi

Cited by 11 publications

References 25 publications

Structural Phase Transition and Possible Valence Instability of Ce$-4f$ Electron Induced by Pressure in CeCoSi

Structural Phase Transition and Possible Valence Instability of Ce$-4f$ Electron Induced by Pressure in CeCoSi

NQR and NMR spectra in the odd-parity multipole material CeCoSi

Semimetallic Orbital Hybridization by Particular Surface Engineering in Ternary Cobalt Silicide to Accelerate Oxygen Evolution Reaction

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