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

Article

关键词: PRESSURE-DEPENDENCE;    SUPERCONDUCTOR;    COMPRESSIBILITY;    TEMPERATURE;   

DOI  :  10.1103/PhysRevB.64.172502

来源: SCIE

【 摘 要 】

We report measurements on MgB2 up to similar 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 p(xy) 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.

【 授权许可】

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