Experimental study of lattice dynamics in LaB6 and YbB6

Smith, Harry; Dolling, G.; Kunii, S.; Koshi, Mitsuo; Liu, B.; Takegahara, Katsuhiko; Kasuya, T.; Goto, T.

doi:10.1016/0038-1098(85)90674-x

Cited by 97 publications

(31 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Then, LaB 6 or YB 6 can be modeled as a Debye solid of the rigid boron framework and metals ions can be treated as independent harmonic oscillators (Einstein oscillators). The local vibrational modes of the La ions are the most important for explanation of the low temperature resisitivity and heat capacity in LaB 6 as was also suggested by the neutron experiments of Smith et al [7] showing rather rapid flattening of the acoustic modes near 13 meV due to non-interacting vibrations of La ions. Some of us [8] have measured the EPI function of LaB 6 directly by the point-contact spectroscopy (PCS) detecting the whole set of 8 modes starting from the prominent peak at 13-15 meV up to 160 meV with the resulting electron-phonon coupling constant λ ≈ 0.15 showing very weak electron-phonon coupling in the system.…”

Section: Introductionmentioning

confidence: 60%

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB₆

Szabó

Girovský

Kačmarčı́k

et al. 2013

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Lortz et al. [Phys. Rev. B 73, 024512 (2006)] have utilized specific heat and resistivity measurements as "thermal spectroscopies" to deconvolve the spectrum of the electron-phonon interaction in YB6 assuming a major role of the low frequency phonon mode in mediating superconductivity. Here, we present direct point-contact spectroscopy studies of the superconducting interaction in this system. As a result the normalized superconducting gap reveals a strong coupling with 2∆/kBTc = 4 and moreover the spectra contain nonlinearities typical of the electron-phonon interaction at energies around 8 meV. The in-magnetic-field measurements evidence that the phonon features found in the second derivative of the current-voltage characteristics are due to the energy dependence of the superconducting energy gap as their energy position shrinks equally as the gap is closing. This is a direct proof that the superconducting coupling in the system is due to the low energy Einstein-like phonon mode associated with the yttrium ion vibrations in a perfect agreement with determinations from bulk measurements.

show abstract

Section: Introductionmentioning

confidence: 60%

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB₆

Szabó

Girovský

Kačmarčı́k

et al. 2013

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Figure 2 shows the comparison with the phonon branches determined by inelastic neutron scattering on LaB by Smith et al (10). This allows the attribution of the 104 cm\ Raman band to the acoustical phonon branch at the boundary of the Brillouin zone and of the 204 cm\ band to the lowest optical phonon branches at the point.…”

Section: For Labmentioning

confidence: 96%

FT Raman Spectroscopy of Some Metal Hexaborides

Schmechel¹,

Werheit²,

Paderno

1997

Journal of Solid State Chemistry

View full text Add to dashboard Cite

“…A determination of the PDOS by inelastic neutron scattering on single crystals is not available for YB 6 , but dispersion curves up to ϳ60 meV are known for the isostructural compounds LaB 6 and SmB 6 . 31,32 In both cases, it was found that the optical modes are separated from the acoustic ones by a wide gap, which can be observed around 24 meV in the PDOS of YB 6 derived from the specific heat ͑Fig. 9 below͒.…”

Section: ͑5͒mentioning

confidence: 99%

Superconductivity mediated by a soft phonon mode: Specific heat, resistivity, thermal expansion, and magnetization ofYB6

et al. 2006

View full text Add to dashboard Cite

The superconductor YB 6 has the second highest critical temperature T c among the boride family MB n . We report measurements of the specific heat, resistivity, magnetic susceptibility, and thermal expansion from 2 to 300 K, using a single crystal with T c = 7.2 K. The superconducting gap is characteristic of medium-strong coupling. The specific heat, resistivity, and expansivity curves are deconvolved to yield approximations of the phonon density of states F͑͒, the spectral electron-phonon scattering function ␣ tr 2 F͑͒, and the phonon density of states weighted by the frequency-dependent Grüneisen parameter ␥ G ͑͒F͑͒, respectively. Lattice vibrations extend to high frequencies Ͼ100 meV, but a dominant Einstein-like mode at ϳ8 meV, associated with the vibrations of yttrium ions in oversized boron cages, appears to provide most of the superconducting coupling and gives rise to an unusual temperature behavior of several observable quantities. A surface critical field H c3 is also observed.

show abstract

Experimental study of lattice dynamics in LaB6 and YbB6

Cited by 97 publications

References 19 publications

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB₆

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB₆

FT Raman Spectroscopy of Some Metal Hexaborides

Superconductivity mediated by a soft phonon mode: Specific heat, resistivity, thermal expansion, and magnetization ofYB6

Contact Info

Product

Resources

About

Experimental study of lattice dynamics in LaB6 and YbB6

Cited by 97 publications

References 19 publications

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB6

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB6

FT Raman Spectroscopy of Some Metal Hexaborides

Superconductivity mediated by a soft phonon mode: Specific heat, resistivity, thermal expansion, and magnetization ofYB6

Contact Info

Product

Resources

About

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB₆

Point-contact spectroscopy of the phononic mechanism of superconductivity in YB₆