Resonant x-ray scattering study of diffuse magnetic scattering from the topological semimetals <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>EuCd</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>EuCd</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Sb</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>
Jian-Rui Soh, E. Schierle, Dayu Yan, Hao Su, D. Prabhakaran, E. Weschke, Yanfeng Guo, Y. G. Shi, A. T. Boothroyd
Abstract
We have investigated the magnetic correlations in the candidate Weyl semimetals ${\mathrm{EuCd}}_{2}P{n}_{2}$ ($Pn=\mathrm{As}$, Sb) by resonant elastic x-ray scattering at the ${\mathrm{Eu}}^{2+}$ ${M}_{5}$ edge. The temperature and field dependence of the diffuse scattering of ${\mathrm{EuCd}}_{2}{\mathrm{As}}_{2}$ provide direct evidence that the Eu moments exhibit slow ferromagnetic (FM) correlations well above the N\'eel temperature. By contrast, the diffuse scattering in the paramagnetic phase of isostructural ${\mathrm{EuCd}}_{2}{\mathrm{Sb}}_{2}$ is at least an order of magnitude weaker. The FM correlations present in the paramagnetic phase of ${\mathrm{EuCd}}_{2}{\mathrm{As}}_{2}$ could create short-lived Weyl nodes.