Specific Heat Study of Non-Fermi Liquid Behavior in CeNi₂Ge₂: Anomalous Peak in Quasi-Particle Density-of-States

Abstract

To investigate the non-Fermi liquid (NFL) behavior in a nonalloyed system CeNi2Ge2, we have measured the temperature and field dependences of the specific heat C on a CeNi2Ge2 single crystal. The distinctive temperature dependence of C/T (∼ α − β √ T ) is destroyed in almost the same manner for both field directions of B//c-axis and B//a-axis. The overall behavior of C(T, B) and the low-temperature upturn in χ(T ) can be reproduced, assuming an anomalous peak of the quasi-particle-band density-of-states (DOS) at the Fermi energy possessing √ ǫ energy dependence. Absence of residual entropy around T = 0 K in B ∼ 0 T has been confirmed by the magnetocaloric effect measurements, which are consistent with the present model. The present model can also be applied to the NFL behavior in CeCu5.9Au0.1 using a ln(ǫ)-dependent peak in the DOS. Possible origins of the peak in the DOS are discussed.

Evidence for momentum-dependent heavy-fermionic electronic structures: Soft x-ray ARPES for the superconductor CeNi2Ge2 in the normal state

“…where m denotes the component of the spin-orbital degeneracy N = 2 of the 7 states in the crystalline electric field scheme of CeNi 2 Ge 2 [56]…”

Ultra-high vacuum compatible preparation chain for intermetallic compounds

“…31 It is a heavy-fermion metal that exhibits non-Fermi liquid behavior and is discussed as being close to an antiferromagnetic quantum critical point at ambient pressure. [32][33][34][35][36][37][38][39][40][41][42][43] A drop of the resistivity below ∼0.1 K reported by several groups has been attributed to incipient superconductivity. 37,39,[44][45][46][47] A large number of studies suggests that the lowtemperature physical properties of CeNi 2 Ge 2 , such as the electrical resistivity or the specific heat, sensitively depend on the detailed composition and the crystalline quality.…”