Abstract

Kondo insulator materials such as CeRhAs, CeRhSb, YbB₁₂, Ce₃Bi₄Pt₃, and SmB₆, are 3d, 4f and 5f intermetallic compounds. At high temperatures they behave like metals but a gap Δ in the conduction band opens at the Fermi energy as the temperature is reduced. It has been proposed that the formation of the low-temperature gap is a consequence of the hybridization between the conduction band and the f-electron levels. If this is true, Kondo metal physics should be recovered when the gap is closed at high magnetic fields. We report here specific heat results of Ce₃Bi₄Pt₃ in DC and pulsed magnetic fields up to 60 T. We see evidence for the reduction of the gap in 18 T and a rapid increase of the Sommerfeld coefficient in 30T>H>40T. Numerical results and the analysis of the data with the Coqblin–Schrieffer model prove a field-induced Kondo insulator-to-Kondo metal crossover.

Author Keywords: Specific heat; Kondo insulators; Pulsed magnetic fields

Article Outline

1. Introduction

2. Low magnetic fields

3. High magnetic fields

4. Discussion

5. Conclusions

Acknowledgements

References