Fluctuation-induced first order transition due to Griffiths anomalies of the Cluster glass phase

Abstract

In itinerant magnetic systems with disorder, the quantum Griffiths phase at T=0 is unstable to formation of a cluster glass (CG) of frozen droplet degrees of freedom. In the absence of the fluctuations associated with these degrees of freedom, the transition from the paramagnetic Fermi liquid (PMFL) to the ordered phase proceeds via a conventional second-order quantum phase transition. However, when the Griffiths anomalies due to the broad distribution of local energy scales are included, the transition is driven first-order via a novel mechanism for a fluctuation induced first-order transition. At higher temperatures, thermal effects restore the transition to second-order. Implications of the enhanced non-Ohmic dissipation in the CG phase are briefly discussed.

arXiv comment11 pages, 5 figures, paper to appear in the Proceedings of SPIE International Conference "Fluctuations and Noise 2007", Florence, Italy, 20-24 May, 2007

References in corpus (11)

• Colossal Magnetoresistance is a Griffiths Singularity
• Infinite-randomness quantum Ising critical fixed points
• Disorder-Driven Non-Fermi Liquid Behavior of Correlated Electrons
• Absence of spontaneous magnetic order at non-zero temperature in one- and two-dimensional Heisenberg and XY systems with long-range interactions
• Disorder-induced rounding of certain quantum phase transitions
• Quantum Griffiths effects in itinerant Heisenberg magnets
• Melting of the Electron Glass
• Geometrical destruction of the global phase coherence in ultrathin superconducting cylinders
• On quantum Griffiths effects in metallic systems
• Absence of conventional quantum phase transitions in itinerant systems with disorder
• Disorder induced non-Fermi liquid near a metal-superconductor quantum phase transition