Structural discontinuity in the hexagonal RTA1 compounds : Experiments and density-functional theory calculations

• An anomalous behavior of the lattice parameters is reported for RTAl and R(T,T-')Al compounds, with R a rare-earth element and T and T-' transition metals or Cu. In these compounds, which crystallize in the hexagonal ZrNiAl-type of structure, an abrupt transition in the temperature or composition dependence of the lattice constants a and c is observed with the common feature that values of the c/a ratio around 0.565-0.575 are generally not realized. Total-energy calculations based on density-functional theory show the occurrence of two close energy minima, which explains the observed structural instability and the associated transitions.

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NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

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Physics

Fysik

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