Single crystal investigation of proposed type-II Weyl semimetal CeAlGe

• Main Authors: Hodovanets, H, Eckberg, C. J, Zavalij, P. Y, Kim, H, Lin, W. -C, Zic, M, Campbell, D. J, Higgins, J. S, Paglione, J
• Format: Journal Article
• Language: English
• Published: 13-08-2018
• Subjects: Physics - Strongly Correlated Electrons
• DOI: 10.48550/arxiv.1808.04434

Phys. Rev. B 98, 245132 (2018) 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 $\Delta$ = 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 $\mu_B$/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
$\bf{H}\|\bf{c}$.