Paramagnetic Excited State of FeSi

Jaccarino, V.; Wertheim, G. K.; Wernick, J. H.; Walker, L. R.; Arajs, Sigurds

doi:10.1103/physrev.160.476

Cited by 432 publications

(323 citation statements)

References 8 publications

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“…The temperature-induced paramagnetic susceptibility and the associated Shottky-like electronic specific heat could be analyzed either in the framework of low (S=0) to high (S=1) spin state transition in the localized spin model, 29 or as a Pauli susceptibility of itinerant electrons in the itinerant narrow-gap picture similar to FeSi. 31,37 A well-defined singlet-triplet magnetic excitation between the crystal field split spin states is expected around ≈ 50 meV in the localized spin picture. Only a broad continuum of magnetic excitations corresponding to correlated magnetic states of excited itinerant electrons would be expected in the band picture.…”

Section: Discussionmentioning

confidence: 99%

“…1 similar to the picture proposed for FeSi. 31,37 There is no local spins and local magnetic moments in this scenario, and only a weak and broad signal is expected in a magnetic neutron scattering experiment. This is consistent with the weak temperature-induced quasi-elastic paramagnetic scattering observed by neutrons in FeSi.…”

Section: Fesb2 Crystal and Electronic Structurementioning

confidence: 99%

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Absence of localized-spin magnetism in the narrow-gap semiconductor FeSb2

et al. 2011

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We report the inelastic neutron scattering measurements aimed at investigating the origin of temperature-induced paramagnetism in narrow-gap semiconductor FeSb2. We find that inelastic response for energies up to 60 meV and at temperatures ≈ 4.2 K, ≈ 300 K and ≈ 550 K is essentially consistent with the scattering by lattice phonon excitations. We observe no evidence for a well-defined magnetic peak corresponding to the excitation from the non-magnetic S = 0 singlet ground state to a state of magnetic multiplet in the localized spin picture. Our data establish the quantitative limit of S 2 ef f 0.25 on the fluctuating local spin. However, a broad magnetic scattering continuum in the 15 meV to 35 meV energy range is not ruled out by our data. Our findings make description in terms of the localized Fe spins unlikely and suggest that paramagnetic susceptibility of itinerant electrons is at the origin of the temperature-induced magnetism in FeSb2.

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Section: Discussionmentioning

confidence: 99%

Section: Fesb2 Crystal and Electronic Structurementioning

confidence: 99%

Absence of localized-spin magnetism in the narrow-gap semiconductor FeSb2

et al. 2011

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“…In the insets an expanded view of the low temperature re ectivity and conductivity is shown in the frequency interval from 150 to 500 cm 1 using a linear scale. The data are characterized by a strong temperature dependence up to 7 000 cm 1 . At room temperature the material behaves as a dirty metal: it does not show a sharp Drude peak at low frequency and the dc-conductivity dc 4 000 1 cm 1 we found with dc-resistivity measurements is much smaller than the typical values for transition metals ( 100 000 1 cm 1 ).…”

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confidence: 99%

“…FeSi has a cubic structure B20 (space-group P 2 1 phonons. Moreover, while most of these peaks have already been observed 7,8], the line at 347 cm 1 has not been resolved before with infrared spectroscopy, possibly due to inhomogeneous broadening of the lines, as it is rather close to the 329 cm 1 mode.…”

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confidence: 99%

“…Bruker system for the far-infrared region (50 -700 cm 1 ) and a DA3 Bomem system for frequencies higher than 600 cm 1 . A liquid helium ow cryostat has been used to study the temperature dependent re ectivity from 4 K to 300 K. The absolute re ectivities were obtained by calibrating the data acquired on the sample against a gold mirror from low frequency to 1 500 cm 1 and an aluminum mirror for higher frequencies.…”

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confidence: 99%

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Optical phonons in the reflectivity spectrum of FeSi

Damascelli

Schulte

Marel

et al. 1997

Physica B: Condensed Matter

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We measured the re ectivity of a single crystal of FeSi from the far-infrared to the visible region (50-20 000 cm 1 ), varying the temperature between 4 and 300 K. The optical conductivity function was obtained via Kramers-Kronig analysis. We observed a dirty metal-like behavior at room temperature and the opening of a gap of 70 meV at low temperature. Of the ve optical phonons expected from group theory analysis for this material only four have been observed in the far-infrared region.

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