Ground state of Ce${}_3$Bi${}_4$Pd${}_3$ unraveled by hydrostatic pressure

Abstract

Noncentrosymmetric Ce${}_3$Bi${}_4$Pd${}_3$ has attracted a lot of attention as a candidate for strongly correlated topological material, yet its experimental ground state remains a matter of contention. Two conflicting scenarios have emerged from a comparison to prototypical Kondo insulator Ce${}_3$Bi${}_4$Pt${}_3$: either Ce${}_3$Bi${}_4$Pd${}_3$ is a spin-orbit-driven topological semimetal or a Kondo insulator with smaller Kondo coupling than its Pt counterpart. Here we determine the ground state of Ce${}_3$Bi${}_4$Pd${}_3$ via electrical resistivity measurements under hydrostatic pressure, which is a clean symmetry-preserving tuning parameter that increases hybridization but virtually preserves spin-orbit coupling. Ce${}_3$Bi${}_4$Pd${}_3$ becomes more insulating under pressure, which is a signature of Ce-based Kondo insulating materials. Its small zero-pressure gap increases quadratically with pressure, similar to the behavior observed in the series Ce${}_3$Bi${}_4$(Pt${}_{1-x}$Pd${}_x$)${}_3$, which indicates that Pt substitution and applied pressure have a similar effect. Our result not only demonstrates that Kondo coupling, rather than spin-orbit coupling, is the main tuning parameter in this class of materials, but it also establishes that Ce${}_3$Bi${}_4$Pd${}_3$ has a narrow-gap Kondo insulating ground state.

6 pages, 4 Figures, includes Supplementary Information (6 pages, 5 Figures)

References in corpus (7)

• Topological Insulators with Inversion Symmetry
• The Quantum Spin Hall Effect: Theory and Experiment
• Topological Semimetals
• On the $Z_2$ classification of Quantum Spin Hall Models
• Metal-Insulator-Like Behavior in Semimetallic Bismuth and Graphite
• Superconductivity at 5.4 K in $\beta$-Bi${}_2$Pd
• Pressure induced superconductivity in Bi single crystals

Cited by in corpus (3)

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• Localized f-electron magnetism in the semimetal Ce3Bi4Au3
• Ce${}_3$Bi${}_4$Ni${}_3$ $-$ A large hybridization-gap variant of Ce${}_3$Bi${}_4$Pt${}_3$