unraveled by hydrostatic pressure

Noncentrosymmetric Ce₃Bi₄Pd₃ has recently attracted tremendous attention as a strongly correlated topological semimetal candidate [1]. Conflicting experimental results, however, argue for either a Weyl Kondo semimetallic or a narrow-gap Kondo insulating ground state [2-4]. Using electrical transport measurements under hydrostatic pressure, we find that Ce₃Bi₄Pd₃ becomes progressively more insulating with increasing pressure, a behavior typical of Ce-based Kondo insulators such as Ce₃Bi₄Pt₃. Moreover, the hybridization gap shows a quadratic increase with pressure akin to the effect of Pt substitution observed in Ce₃Bi₄(Pt_1-xPd_x)₃ series [2]. The pressure dependence of the carrier density, obtained from Hall resistivity measurements on a microstructure device of Ce₃Bi₄Pd₃, is in excellent agreement with the enhancement of the insulating gap under pressure. Our results suggest that the Kondo coupling prevails as the primary tuning parameter in this class of materials and Ce₃Bi₄Pd₃ has a narrow-gap Kondo insulating ground state.

[1] H.-H. Lai et al., Proc. Natl. Acad. Sci. U.S.A. 115, 93 (2018).

[2] S. Dzsaber et al., Phys. Rev. Lett. 118, 246601(2018).

[3] S. Dzsaber et al., Proc. Natl. Acad. Sci. U.S.A. 118, e2013386118 (2021).

[4] S. K. Kushwaha et al., Nat. Comm. 10, 5487 (2019).