Abstract
For solid-solution Fermi surface evolution is mapped via Bloch spectral functions calculated using density functional theory implemented in Korringa-Kohn-Rostoker multiple scattering theory with the coherent-potential approximation. Spectral functions reveal electronic dispersion, topology, orbital character, and broadening (electron-lifetime effects) due to chemical disorder. Dissolution of electron cylinders occurs near with a nonuniform, topological (Lifshitz) transition, reducing the interband interactions; yet the dispersion maintains its or character. Formation energies indicate alloying at , as observed, and a tendency for segregation on the K-rich () side, explaining the difficulty of controlling sample quality and the conflicting results between characterized electronic structures. Our results reveal Fermi surface transitions in alloyed samples that influence to nodal superconductivity and suggest the origin for deviations of common trends in Fe-based superconductors, such as Bud’ko-Ni-Canfield scaling.
- Received 11 November 2013
DOI:https://doi.org/10.1103/PhysRevLett.112.156401
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