Volume 111, Number 6, September 2015
|Number of page(s)||5|
|Section||Interdisciplinary Physics and Related Areas of Science and Technology|
|Published online||30 September 2015|
Phonons in ultra-high melting temperature Ta2C
1 Texas Center for Superconductivity and Department of Mechanical Engineering, University of Houston Houston, TX 77204, USA
2 Clarkson Aerospace Corporation - 2320 La Branch St, Houston, TX 77004, USA
3 Texas Center for Superconductivity, University of Houston - Houston, TX 77204, USA
Received: 29 June 2015
Accepted: 9 September 2015
We present a Raman scattering study of Ta2C complemented with density functional perturbation theory (DFPT) calculations. The polarized Raman spectra of Ta2C reveal all symmetry-allowed Raman phonons at and . The phonon dispersion of Ta2C shows that the zone-center Eg frequency is lower than that of the zone-boundary acoustic phonons, resulting in small anharmonic renormalization of the Eg phonon. We demonstrate that the electron-phonon interactions account for almost half of the measured phonon linewidths. The calculated electron-phonon coupling strength λ is not high enough to produce phonon-mediated superconductivity, a result in agreement with experimental observations.
PACS: 81.05.Je – Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides) / 63.20.D- – Phonon states and bands, normal modes, and phonon dispersion
© EPLA, 2015
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