Results of highly precise all-electron local-density calculations are presented for the quasi-two-dimensional superconductors La2-xMxCuOx (M=Ba,Sr,) with x=0 and correlated with a number of observed properties of these materials for varying x. The dominant role of the van Hove saddle-point singularity (SPS) on the density of states (DOS) and the DOS-derived properties (specific heat, magnetic susceptibility, Tc) is emphasizedas is the fact that this SPS represents the classic Lifshitz transition versus x (and/or pressure) with its possible thermodynamic and galvanomagnetic anomalies. Estimates of the enhancement factor from a variety of measured specific-heat values and our calculated DOS indicate that these materials may possibly be weak-coupling superconductors. Crude estimates of coherent lengths (and) and upper critical fields (Hc2 and Hc2) are presented.
ASJC Scopus subject areas
- Condensed Matter Physics