Correa, V. F., P. Pedrazzini, D. G. Franco, A. J. Rosa, B. Rubrecht, and N. Haberkorn. "Lowtemperature thermal expansion of the topological material candidates βPtBi2 and βPdBi2." Physica B – Condensed Matter 641 (2022): 414102.
Abstract: We report on the lowtemperature ($T <$ 120 K) thermal expansion of the bismuthbased topological semimetal $\beta$PtBi$2$ and topological superconductor $\beta$PdBi$2$ candidates.
The linear thermalexpansion coefficient of tetragonal $\beta$PdBi$2$ shows a pronounced anisotropy between the $a$ and $c$axis while the volume thermalexpansion coefficient $\alphaV$($\beta$PdBi$2$) is considerable larger than $\alphaV$($\beta$PtBi$_2$).
The coefficient $\alphaV$($\beta$PtBi$2$) nearly matches the experimental specific heat, from which a Debye temperature $\thetaD =$ 199 K is obtained. On the other hand, $\alphaV$($\beta$PdBi$2$) reasonably fits the Debye model with $\thetaD =$ 138 K, extracted from the lowtemperature specific heat.
An almost constant Gr\"uneisen parameter $\Gamma \approx$ 2 is obtained for both compounds.
No magnetostriction is observed in any of both compounds up to $\mu_0 H =$ 16 T.
We compare our results with other Bibased topological materials.
