Selected Publications

Anisotropic Physical Properties of the Kondo Semimetal CeCu1.11As2

L. Cvitkovich, D. A. Zocco, G. Eguchi, M. Waas, R. Svagera, B. Stöger, R. Mondal, A. Thamizhavel, S. Paschen

The recently proposed novel materials class called Weyl–Kondo semimetal (WKSM) is a time reversal invariant but inversion symmetry broken Kondo semimetal in which Weyl nodes are pushed to the Fermi level by the Kondo interaction. Here we explore whether CeCu1+xAs2 may be a new WKSM candidate. We report on its single-crystal growth, structure determination and physical properties investigation. Previously published studies on polycrystalline samples suggest that it is indeed a Kondo semimetal, which is confirmed by our investigations on single crystals. X-ray diffraction reveals that CeCu1+xAs2 crystallizes in a tetragonal centrosymmetric structure, although the inversion symmetry could still be broken locally due to partially occupied Cu sites. Chemical analysis results in an average occupation x = 0.11(1). The electrical resistivity increases logarithmically with decreasing temperature, and saturates below 10?K. A Kondo temperature TK≈4K is extracted from entropy, estimated from the specific heat measurements. From Hall effect experiments, a charge carrier density of 8.8 × 1020?cm−3 is extracted, a value characteristic of a semimetal. The magnetization shows pronounced anisotropy, with no evidence of magnetic ordering down to 0.4?K. We thus classify CeCu1.11As2 as a tetragonal Kondo semimetal with anisotropic magnetic properties, with a possibly broken inversion symmetry, thus fulfilling the necessary conditions for a WKSM state.

JPS Conf. Proc 30 011020 (2020)

doi: 10.7566/JPSCP.30.011020