Absence of a structural transition up to 40 GPa in MgB2 and the relevance of magnesium nonstoichiometry

P. Bordet, M. Mezouar, M. Núñez-Regueiro, M. Monteverde, M. D. Núñez-Regueiro, N. Rogado, K. A. Regan, M. A. Hayward, T. He, S. M. Loureiro, R. J. Cava

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Abstract

We report measurements on MgB2 up to ∼40 GPa. Increasing pressure yields a monotonous decrease of the lattice parameters and of the c/a ratio, but no structural transition down to parameters smaller than those of AlB2. The transition superconducting temperature also decreases with temperature in a sample-dependent way. The results are explained by an increase of the filling of the two-dimensional pxy bands with pressure, the Mg stoichiometry determining the starting position of the Fermi level. Our measurements indicate that these hole bands are the relevant ones for superconductivity.

Original languageEnglish (US)
Article number172502
Pages (from-to)1725021-1725024
Number of pages4
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume64
Issue number17
StatePublished - Nov 1 2001

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Bordet, P., Mezouar, M., Núñez-Regueiro, M., Monteverde, M., Núñez-Regueiro, M. D., Rogado, N., Regan, K. A., Hayward, M. A., He, T., Loureiro, S. M., & Cava, R. J. (2001). Absence of a structural transition up to 40 GPa in MgB2 and the relevance of magnesium nonstoichiometry. Physical Review B - Condensed Matter and Materials Physics, 64(17), 1725021-1725024. [172502].