Abstract

CeCu 2 Si 2 is an exemplary correlated electron metal that features two domes of unconventional superconductivity in its temperature-pressure phase diagram. The first dome surrounds an antiferromagnetic quantum critical point, whereas the more exotic second dome may span the termination point of a line of f -electron valence transitions. This behavior has received intense interest, but what has been missing are ways to access the high pressure behavior under milder conditions. Here we study Si → P chemical substitution, which compresses the unit cell volume but simultaneously weakens the hybridization between the f - and conduction electron states and encourages complex magnetism. At concentrations that show magnetism, applied pressure suppresses the magnetic ordering temperature and superconductivity is recovered for samples with low disorder. These results reveal that the electronic behavior in this system is controlled by a nontrivial combination of effects from unit cell volume and electronic shell filling. Guided by this topography, we discuss prospects for uncovering a valence fluctuation quantum phase transition in the broader family of Ce-based ThCr 2 Si 2 -type materials through chemical substitution.

Department(s)

Physics, Astronomy, and Materials Science

Document Type

Article

DOI

https://doi.org/10.1103/physrevmaterials.1.034801

Rights Information

© 2017 American Physical Society

Keywords

antiferromagnetism, electrical conductivity, entropy, kondo effect, magnetic anisotropy, magnetic phase transitions, magnetic susceptibility, phase diagrams, pressure effects, specific heat, superconducting phase transition

Publication Date

2017

Journal Title

Physical Review Materials

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