Phase separation in the nonequilibrium Verwey transition in magnetite

Randi F, Vergara I, Novelli F, Esposito M, Dell'Angela M, Brabers VAM, Metcalf P, Kukreja R, Duerr HA, Grueninger M, Parmigiani F, Fausti D (2016)

Publication Type: Journal article

Publication year: 2016

Journal

Physical Review B American Physical Society

Book Volume: 93

Article Number: 054305

Journal Issue: 5

DOI: 10.1103/PhysRevB.93.054305

Abstract

We present equilibrium and out-of-equilibrium studies of the Verwey transition in magnetite. In the equilibrium optical conductivity, we find a steplike change at the phase transition for photon energies below about 2 eV. The possibility of triggering a nonequilibrium transient metallic state in insulating magnetite by photo excitation was recently demonstrated by an x-ray study. Here we report a full characterization of the optical properties in the visible frequency range across the nonequilibrium phase transition. Our analysis of the spectral features is based on a detailed description of the equilibrium properties. The out-of-equilibrium optical data bear the initial electronic response associated to localized photoexcitation, the occurrence of phase separation, and the transition to a transient metallic phase for excitation density larger than a critical value. This allows us to identify the electronic nature of the transient state, to unveil the phase transition dynamics, and to study the consequences of phase separation on the reflectivity, suggesting a spectroscopic feature that may be generally linked to out-of-equilibrium phase separation.

Authors with CRIS profile

Daniele Fausti

Involved external institutions

Università degli Studi di Trieste IT Italy (IT) Universität zu Köln DE Germany (DE) Elettra Sincrotrone Trieste S.C.p.A. IT Italy (IT) Eindhoven University of Technology / Technische Universiteit Eindhoven (TU/e) NL Netherlands (NL) Purdue-University US United States (USA) (US) Stanford National Accelerator Laboratory (SLAC) US United States (USA) (US)

How to cite

APA:

Randi, F., Vergara, I., Novelli, F., Esposito, M., Dell'Angela, M., Brabers, V.A.M.,... Fausti, D. (2016). Phase separation in the nonequilibrium Verwey transition in magnetite. Physical Review B, 93(5). https://dx.doi.org/10.1103/PhysRevB.93.054305

MLA:

Randi, Francesco, et al. "Phase separation in the nonequilibrium Verwey transition in magnetite." Physical Review B 93.5 (2016).

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