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arXiv · 1808.04434

Single crystal investigation of proposed type-II Weyl semimetal CeAlGe

H. Hodovanets·C. J. Eckberg·P. Y. Zavalij·H. Kim·W. -C. Lin·M. Zic·D. J. Campbell·J. S. Higgins·J. Paglione
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Abstract

We present details of materials synthesis, crystal structure, and anisotropic magnetic properties of single crystals of CeAlGe, a proposed type-II Weyl semimetal. Single-crystal x-ray diffraction confirms that CeAlGe forms in noncentrosymmetric I4$_1$md space group, in line with predictions of non-trivial topology. Magnetization, specific heat and electrical transport measurements were used to confirm antiferromagnetic order below 5 K, with an estimated magnon excitation gap of $Δ$ = 9.11 K from heat capacity and hole-like carrier density of 1.44 $\times$ 10$^{20}$ cm$^{-3}$ from Hall effect measurements. The easy magnetic axis is along the [100] crystallographic direction, indicating that the moment lies in the tetragonal $\it{ab}$-plane below 7 K. A spin-flop transition to less than 1 $μ_B$/Ce is observed to occur below 30 kOe at 1.8 K in the $M(H)$ ($\bf{H}\|\bf{a}$) data. Small magnetic fields of 3 kOe and 30 kOe are sufficient to suppress magnetic order when applied along the $\it{a}$- and $\it{c}$-axes, respectively, resulting in a complex $\it{T-H}$ phase diagram for $\bf{H}\|\bf{a}$ and a simpler one for $\bf{H}\|\bf{c}$.

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H. Hodovanets, C. J. Eckberg, P. Y. Zavalij, H. Kim, W. -C. Lin, M. Zic, D. J. Campbell, J. S. Higgins, J. Paglione. 2018-08-13. Single crystal investigation of proposed type-II Weyl semimetal CeAlGe. https://doi.org/10.1103/physrevb.98.245132

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