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Phonon Softening in Superconducting Diamond

M. Hoesch·T. Fukuda·T. Takenouchi·J. P. Sutter·S. Tsutsui·A. Q. R. Baron·M. Nagao·Y. Takano·H. Kawarada·J. Mizuki
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Abstract

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 CVD-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 lambda= 0.33.

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M. Hoesch, T. Fukuda, T. Takenouchi, J. P. Sutter, S. Tsutsui, A. Q. R. Baron, M. Nagao, Y. Takano, H. Kawarada, J. Mizuki. 2007-04-13. Phonon Softening in Superconducting Diamond. https://arxiv.org/abs/cond-mat/0512424

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