Ce\(_3\)Bi\(_4\)Ni\(_3\) \(-\) A large hybridization-gap variant of Ce\(_3\)Bi\(_4\)Pt\(_3\)

• Published in: arXiv.org 2024-06
• Main Authors: Kirschbaum, D M, Yan, X, Waas, M, Svagera, R, Prokofiev, A, Stöger, B, Giester, G, Rogl, P, D -G Oprea, Felser, C, Valentí, R, Vergniory, M G, Custers, J, Paschen, S, Zocco, D A
• Format: Article
• Language: English
• Subjects: Atomic properties; Energy gap; Fermions; Hall effect; Magnetic permeability; Palladium; Physical properties; Platinum; Pressure effects
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2311.17903

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.