AbstractKondo insulators are expected to transform into metals under a sufficiently strong magnetic field. The closure of the insulating gap stems from the coupling of a magnetic field to the electron spin, yet the required strength of the magnetic field–typically of order 100 T–means that very little is known about this insulator-metal transition. Here we show that Ce$${}_{3}$$3Bi$${}_{4}$$4Pd$${}_{3}$$3, owing to its fortuitously small gap, provides an ideal Kondo insulator for this investigation. A metallic Fermi liquid state is established above a critical magnetic field of only $${B}_{{\rm{c}}}\approx$$Bc≈ 11 T. A peak in the strength of electronic correlations near $${B}_{{\rm{c}}}$$Bc, which is evident in transport and susceptibility measurements, suggests that Ce$${}_{3}$$3Bi$${}_{4}$$4Pd$${}_{3}$$3 may exhibit quantum criticality analogous to that reported in Kondo insulators under pressure. Metamagnetism and the breakdown of the Kondo coupling are also discussed.
Fragility of the Kondo insulating gap against disorder: Relevance to recent puzzles in topological Kondo insulators
