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Absence of a structural transition up to 40 GPa inMgB2and the relevance of magnesium nonstoichiometry
- Source :
- Physical Review B. 64
- Publication Year :
- 2001
- Publisher :
- American Physical Society (APS), 2001.
-
Abstract
- We report measurements on ${\mathrm{MgB}}_{2}$ up to $\ensuremath{\sim}40 \mathrm{GPa}.$ 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 ${\mathrm{AlB}}_{2}.$ 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 ${p}_{\mathrm{xy}}$ 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.
Details
- ISSN :
- 10953795 and 01631829
- Volume :
- 64
- Database :
- OpenAIRE
- Journal :
- Physical Review B
- Accession number :
- edsair.doi...........40c6666d624e721e635aea6ebb4ad2ba