Electronic structure and electron-phonon coupling in stoichiometric and defective hydrides (M=Ca, Sr, Eu, Yb)
Por:
Orgaz E., Mazel V., Gupta M.
Publicada:
1 ene 1996
Resumen:
On the basis of electron transfer from the divalent element to the (Formula presented) entities, the perovskite structure M(Formula presented) (M=Sr, Eu, Yb) are expected to have similar electronic states at the Fermi energy as superconducting Pd-(Formula presented) and Pd-noble-metal-(Formula presented) and thus could be potential candidates for superconductivity. With this motivation, we have investigated the electronic structure and some aspects of the electron-phonon coupling in these hydrides using the ab initio augmented plane-wave method, and the results of the energy bands, the total and partial wave analysis of the density of states, and the electronic contribution, (Formula presented) to the electron-phonon coupling are presented. Similar studies for the hydrogen defective material (Formula presented) are also included. We have found that all these compounds are metallic with essentially filled Pd-d bands and a small density of states at Fermi level as in PdH. Nevertheless, the calculated values of (Formula presented), which govern the contribution of the hydrogen atoms to the electron-optical phonon coupling parameter ?, although sizeable, are lower than in PdH. This would indicate that these compounds, if superconducting, would have lower values of the superconducting transition temperatures (Formula presented) than in PdH. © 1996 The American Physical Society.
Filiaciones:
Orgaz E.:
Université de Paris-Sud, URA-446 Centre National de la Recherche Scientifique, Bât. 415, 91405 Orsay-Cedex, France
Mazel V.:
Université de Paris-Sud, URA-446 Centre National de la Recherche Scientifique, Bât. 415, 91405 Orsay-Cedex, France
Gupta M.:
Université de Paris-Sud, URA-446 Centre National de la Recherche Scientifique, Bât. 415, 91405 Orsay-Cedex, France
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