Excess heat capacity in Ce-based heavy fermion magnets

Ce-based heavy fermion magnets are prototypical systems displaying quantum critical phase transitions, non-Fermi liquid behavior, and often superconductivity under modest amounts of applied pressure. Recently, inelastic neutron scattering measurements have validated a minimal low energy effective model that was derived from first principles calculations on the heavy fermion antiferromagnet CeIn₃ [1]. The magnon dispersion obtained from the inelastic neutron scattering measurements motivates us to revisit earlier heat capacity measurements. Surprisingly, we find that after combining the expected magnon, phonon, and (renormalized) electron contributions that a substantial contribution to the heat capacity remains in the T → 0 limit. This illustrates the presence of additional excitations within the antiferromagnetic state of CeIn₃. We further illustrate that this is a general feature of Ce-based heavy fermion magnets.



[1] W. Simeth, et al. arXiv:2208.02211