title: Thermal avalanches near a Mott transition.
abstract: We probe the volume collapse transition (ΔV/Vo ∼ 15%) between the isostructural γ and α phases (T ∼ 100 K) of Ce0.9Th0.1 using the Hall effect, three-terminal capacitive dilatometry, and electrical resistivity measurements. Hall effect measurements confirm the itinerant ground state as the carrier concentration increases by a factor of 7 in the α phase, γ phase (nH = 5.28 × 10(26) m(-3)), and the α phase (nH = 3.76 × 10(27) m(-3)). We were able to detect a noise spectrum consisting of avalanches while slowly varying the temperature through the hysteretic region. We surmise that the avalanches originate from intergranular stresses at the interfaces between partially transformed high-volume and low-volume phases. The statistical distribution of avalanches obey power laws with energy exponent ϵ ≃ 1.5. Hall effect measurements, combined with universal critical exponents, point to short electron mean-free percolation pathways and carrier localization at phase interfaces. Carrier localization was predicted many years ago for elemental cerium by Johansson (1974 Phil. Mag. 30 469).
authors.affiliation: Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Lashley
authors.forename: K
authors.initials: K
authors.lastname: Gofryk
authors.forename: B
authors.initials: B
authors.lastname: Mihaila
authors.forename: J L
authors.initials: JL
authors.lastname: Smith
authors.forename: E K H
authors.initials: EK
authors.lastname: Salje