We observe strong softening of optical-phonon modes in superconducting (Tc =4.2 K) boron-doped diamond near the Brillouin-zone center using inelastic x-ray scattering from a chemical vapor deposition grown highly oriented sample. The magnitude of the softening, and our observation that it becomes stronger approaching zone center, supports theoretical models suggesting a phonon-mediated pairing mechanism via coupling of optical-phonon modes to Fermi surfaces around the zone center. The electron-phonon coupling parameter is determined as approximately λ=0.33.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2007 4月 18|
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