Sereni, J. G., M. Gomez Berisso, N. C. Canales, M. Deppe, and C. Geibel. "Tuning ground state degeneracy and quantum criticality in Ce_{1x}La_{x}TiGe." Physica Status Solidi (B) Basic Research 247, no. 3 (2010): 707–709.
Abstract: We have tuned the paramagnetic heavy Fermion (HF) system CeTiGe to a more magnetic state and toward quantum criticality (QC) by partially substituting La for Ce. The induced volume expansion leads to a pronounced decrease of the Kondo temperature (T_{K}), from ≈50 K in pure CeTiGe to less than 4 K at large La content. Since the former value is of the order of the crystal field splitting, while the latter is well below, the systems evolves from a large degeneracy N = 6 Kondo system at x = 0 to a conventional N = 2 Kondo system at x ≥ 0:8. There, the first excited crystal field doublets become apparent in the T dependence of the specific heat C_{P}(T) at an excitation energy D_{CF} ≈ 30 K. The reduction of the degeneracy is expected to enhance the decrease of T_{K}, explaining the strong reduction by more than one order of magnitude observed in this system. The decrease of T_{K} drives the system toward QC as evidenced by a divergence of C_{P}(T)/T and x(T) toward low temperatures in the x = 0:8 sample. © 2010 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim.
