Occurrence of two quantum critical points in Yb₂Pd₂Sn or, Yb systems do not behave mirror-like to Ce compounds

Abstract

We report on the discovery of two pressure driven quantum critical points appearing in ternary Yb2Pd2Sn, where the application of pressure of about 1 GPa establishes long-range antiferromagnetic order, but above an upper bound of about 4 GPa, magnetic order vanishes again, giving rise to two phase transitions at zero temperature. Associated with the QCP's in Yb2Pd2Sn, we observe nFl behaviour from precise resistivity measurements. We argue that this emergent behaviour corresponds to two pressure dependent, mutually competing energy scales exerted to the Yb ions. Electronic properties associated with the paramagnetic state below and above the critical pressures disagree, as evident from a negative and a positive Grüneisen parameter, respectively. Our novel finding, without much doubt, is a unique property of Yb systems.