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arXiv · 1812.06074

Pressure dependent intermediate valence behavior in YbNiGa$_{4}$ and YbNiIn$_{4}$

Z. E. Brubaker·R. L. Stillwell·P. Chow·Y. Xiao·C. Kenney-Benson·R. Ferry·D. Popov·S. B. Donald·P. Söderlind·D. J. Campbell·J. Paglione·K. Huang·R. E. Baumbach·R. J. Zieve·J. R. Jeffries
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Abstract

We report a comprehensive structural and valence study of the intermediate valent materials YbNiGa$_{4}$ and YbNiIn$_{4}$ under pressures up to 60 GPa. YbNiGa$_{4}$ undergoes a smooth volume contraction and shows steady increase in Yb-valence with pressure, though the Yb-valence reaches saturation around 25 GPa. In YbNiIn$_{4}$, a change in pressure dependence of the volume and a peak in Yb-valence suggest a pressure induced electronic topological transition occurs around 10-14 GPa. In the pressure region where YbNiIn$_{4}$ and YbNiGa$_{4}$ possess similar Yb-Yb spacings the Yb-valence reveals a precipitous drop. This drop is not captured by density-functional-theory calculations and implies that both the lattice degrees of freedom and the chemical environment play an important role in establishing the valence of Yb.

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Z. E. Brubaker, R. L. Stillwell, P. Chow, Y. Xiao, C. Kenney-Benson, R. Ferry, D. Popov, S. B. Donald, P. Söderlind, D. J. Campbell, J. Paglione, K. Huang, R. E. Baumbach, R. J. Zieve, J. R. Jeffries. 2018-12-14. Pressure dependent intermediate valence behavior in YbNiGa$_{4}$ and YbNiIn$_{4}$. https://doi.org/10.1103/physrevb.98.214115

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