Non-Fermi Liquid State Bounded by a Possible Electronic Topological Transition in ZrZn₂

Abstract

We report high-precision magnetic and transport measurements of ZrZn 2 and present a phase diagram as a function of pressure and magnetic field. The paramagnetic phase is found to be divided into two regions at T ' 0 by a possible electronic topological transition (i.e., a non-symmetry breaking transition) known as the Lifshitz transition, and the two regions are characterized by Fermi and non-Fermi liquid behaviors. These results strongly suggest that the non-Fermi liquid state exists as a stable phase distinguished from the Fermi liquid by the Fermi surface topology. As a possible origin of the non-Fermi liquid behavior, an antiferromagnetic fluctuation arising from the Fermi surface nesting is discussed.

Ferromagnetic quantum criticality: New aspects from the phase diagram of LaCrGe3

“…Similar experimental studies have revealed other wing-structure phase diagrams in UGe 2 [8,30,31] (also shown in Fig. 6 for comparison), Sr 3 Ru 2 O 7 [37], ZrZn 2 [9], UCoAl [35,36,40]. The behavior near the tricritical point could not be studied in Sr 3 Ru 2 O 7 and UCoAl because those compounds are already in the paramagnetic regime at ambient pressure.…”

“…In the same way as pressure can initially decrease the freezing point of water, physicist have been able to use pressure to decrease the Curie temperature to absolute zero temperature, leading to a quantum phase transition. Surprisingly, a variety of unconventional properties have been unveiled near the ferromagnetic quantum phase transition [1], including superconductivity [2][3][4][5], non-Fermi liquid behavior [6], tri-criticality [5,[7][8][9][10], and complex magnetic structures [11][12][13][14][15][16].…”

Metallic quantum ferromagnets

“…3; the observation of tricritical wings by Uhlarz et al (2004) confirmed an earlier suggestion by Kimura et al (2004). The first-order nature of the QPT was confirmed by Kabeya et al (2012Kabeya et al ( , 2013, who also studied crossover phenomena above the tricritical wings. However, the transition is weakly first order and, for p < p c , ZrZn 2 can be reasonably well understood within the SCR theory (Grosche et al, 1995;Smith et al, 2008).…”

Quantum tricritical point in the temperature-pressure-magnetic field phase diagram of CeTiGe3

“…2 and 3. In the case of the transition becoming of the first order, a wing structure was predicted in Ref. 4 and observed in UGe 2 [5] and ZrZn 2 [6]. The case of the appearance of a modulated magnetic phase is more complex [2,3,[7][8][9][10][11][12] and an experimental examples were found in LaCrGe3 [12] and CeRuPO [13].…”