Anharmonicity due to Electron-Phonon Coupling in Magnetite

Abstract

We present the results of inelastic x-ray scattering for magnetite and analyze the energies and spectral widths of the phonon modes with different symmetries in a broad range of temperature 125<T<293 K. The phonon modes with X_4 and Delta_5 symmetries broaden in a nonlinear way with decreasing temperature when the Verwey transition is approached. It is found that the maxima of phonon widths occur away from high-symmetry points which indicates the incommensurate character of critical fluctuations. Strong phonon anharmonicity induced by electron-phonon coupling is discovered within ab initio calculations which take into account local Coulomb interactions at Fe ions. It (i) explains observed anomalous phonon broadening, and (ii) demonstrates that the Verwey transition is a cooperative phenomenon which involves a wide spectrum of phonons coupled to charge fluctuations condensing in the low-symmetry phase.

5 pages, 5 figures, accepted in Physical Review Letters

References in corpus (5)

• Mechanism of the Verwey transition in magnetite
• Resonant X-ray diffraction studies on the charge ordering in magnetite
• Origin of the Verwey transition in magnetite: Group theory, electronic structure, and lattice dynamics study
• High-energy photoemission on Fe3O4: Small polaron physics and the Verwey transition
• Direct observation of t2g orbital ordering in magnetite

Cited by in corpus (14)

• Strong anharmonicity induces quantum melting of charge density wave in 2H-NbSe$\_2$ under pressure
• Jahn-Teller distortion driven magnetic polarons in magnetite
• Short-Range Correlations in Magnetite above the Verwey Temperature
• Discovery of the soft electronic modes of the trimeron order in magnetite
• Lattice dynamics of the heavy fermion compound URu${}_2$Si${}_2$
• Trimeron-phonon coupling in magnetite
• Verwey transition as evolution from electronic nematicity to trimerons via electron-phonon coupling
• Charge order at magnetite Fe3O4(001): surface and Verwey phase transitions
• Influence of isolated and clustered defects on electronic and dielectric properties of wustite
• Transverse acoustic phonon anomalies at intermediate wavevectors in MgV${}_2$O${}_4$
• Dual-stage structural response to quenching charge order in magnetite
• Polarons with arbitrary nonlinear electron-phonon interaction
• Simultaneous mapping of the ultrafast time and fluence dependence of the laser-induced insulator-to-metal transition in magnetite
• Direct observation of Jahn-Teller critical dynamics at a charge-order Verwey transition