paper

Ce $_{3}$ Bi $_{4}$ Ni $_{3}$ $-$ A large hybridization-gap variant of Ce $_{3}$ Bi $_{4}$ Pt $_{3}$

arXiv:2311.17903 · doi:10.1103/PhysRevResearch.6.023242

Abstract

The family of cubic noncentrosymmetric 3-4-3 compounds has become a fertile ground for the discovery of novel correlated metallic and insulating phases. Here, we report the synthesis of a new heavy fermion compound, Ce $_{3}$ Bi $_{4}$ Ni $_{3}$ . It is an isoelectronic analog of the prototypical Kondo insulator Ce $_{3}$ Bi $_{4}$ Pt $_{3}$ and of the recently discovered Weyl-Kondo semimetal Ce $_{3}$ Bi $_{4}$ Pd $_{3}$ . In contrast to the volume-preserving Pt-Pd substitution, structural and chemical analyses reveal a positive chemical pressure effect in Ce $_{3}$ Bi $_{4}$ Ni $_{3}$ relative to its heavier counterparts. Based on the results of electrical resistivity, Hall effect, magnetic susceptibility, and specific heat measurements, we identify an energy gap of 65-70 meV, about eight times larger than that in Ce $_{3}$ Bi $_{4}$ Pt $_{3}$ and about 45 times larger than that of the Kondo-insulating background hosting the Weyl nodes in Ce $_{3}$ Bi $_{4}$ Pd $_{3}$ . We show that this gap as well as other physical properties do not evolve monotonically with increasing atomic number, i.e., in the sequence Ce $_{3}$ Bi $_{4}$ Ni $_{3}$ -Ce $_{3}$ Bi $_{4}$ Pd $_{3}$ -Ce $_{3}$ Bi $_{4}$ Pt $_{3}$ , but instead with increasing partial electronic density of states of the $d$ orbitals at the Fermi energy. To understand under which condition topological states form in these materials is a topic for future studies.

28 pages, 11 figures

Ce3​Bi4​Ni3​ − A large hybridization-gap variant of Ce3​Bi4​Pt3​

Abstract

Ce $_{3}$ Bi $_{4}$ Ni $_{3}$ $-$ A large hybridization-gap variant of Ce $_{3}$ Bi $_{4}$ Pt $_{3}$