Experimental and theoretical studies of vibrational density of states in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>Fe</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>single-crystalline thin films

Handke, B.; Kozłowski, A.; Parliński, K.; Przewoźnik, J.; Ślęzak, T.; Chumakov, A. I.; Niesen, L.; Ka̧kol, Z.; Korecki, J.

doi:10.1103/physrevb.71.144301

Cited by 41 publications

(33 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This mechanism is supported by the observation that the phonon modes stiffen in the insulating state in spite of lattice expansion due to the monoclinic distortion. 48,49,51 One should note also that two Raman modes at frequencies ∼ 39 meV (E g ) and ∼ 83 meV (A 1g ), which strongly depend on U , show the largest anomalies at the transition point. 48,49 In contrast, for the infrared phonons the frequency dependence on U is much weaker and no significant anomalies were found at T V , apart from some changes in the linewidths of these modes.…”

mentioning

confidence: 94%

Origin of the Verwey transition in magnetite: Group theory, electronic structure, and lattice dynamics study

2007

View full text Add to dashboard Cite

The Verwey phase transition in magnetite has been analyzed using the group theory methods. It is found that two order parameters with the symmetries X3 and ∆5 induce the structural transformation from the high-temperature cubic to the low-temperature monoclinic phase. The coupling between the order parameters is described by the Landau free energy functional. The electronic and crystal structure for the cubic and monoclinic phases were optimized using the ab initio density functional method. The electronic structure calculations were performed within the generalized gradient approximation including the on-site interactions between 3d electrons at iron ions -the Coulomb element U and Hund's exchange J. Only when these local interactions are taken into account, the phonon dispersion curves, obtained by the direct method for the cubic phase, reproduce the experimental data. It is shown that the interplay of local electron interations and the coupling to the lattice drives the phonon order parameters and is responsible for the opening of the gap at the Fermi energy. Thus, it is found that the metal-insulator transition in magnetite is promoted by local electron interactions, which significantly amplify the electron-phonon interaction and stabilize weak charge order coexisting with orbital order of the occupied t2g states at Fe ions. This provides a scenario to understand the fundamental problem of the origin of the Verwey transition in magnetite.

show abstract

mentioning

confidence: 94%

Origin of the Verwey transition in magnetite: Group theory, electronic structure, and lattice dynamics study

2007

View full text Add to dashboard Cite

show abstract

“…Recent band-structure calculations including Coulomb interelectron correlations yielded an insulating gap comparable to that experimentally measured [8,9]. Apart from the indirect suggestions on lattice dynamics changing [10,11], recently, the lattice stiffening below T V was directly proved [12]. Consequently, electrons confined to lattice creating small polarons were successfully used to reproduce temperature dependence of resistivity [13].…”

Section: Introductionmentioning

confidence: 90%

Electronic states of magnetite from photoemission spectroscopy ARUPS

Zalecki

Kołodziejczyk

Kozłowski

et al. 2006

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

The valence band photoemission spectra of epitaxially grown film and bulk single crystal of magnetite were measured by the angle-resolved ultraviolet photoemission spectroscopy (ARUPS) at 300 K and 120 K. Four main features of the electron photoemission were observed at about -1.0 eV, -3.5 eV, -5.0 eV and -6.5 eV below the chemical potential; they are rather strongly dependant on structure and preparation of surface. The three higher-energy features showed significant energy dispersion. The ARUPS spectra were compared to the accessible band structure calculations. Special attention was paid to the leading edge of the emission at -1.0 eV of the low-temperature spectrum where an insulating gap should be observed.

show abstract

“…Specifically, the tetrahedral site holds F e 3+ ions, while the octahedral site houses both F e 2+ and F e 3+ ions. Two studies have considered different contributions to phonon DOS from the two sites in magnetite [7,8]. In cases of amorphous materials, all the lattice sites are nonequivalent in principle.…”

Section: Multiple Sitesmentioning

confidence: 99%

Some notes on data analysis for nuclear resonant inelastic x-ray scattering

2016

Hyperfine Interact

View full text Add to dashboard Cite

Nuclear Resonant Inelastic X-ray Scattering (NRIXS) is a spectroscopy method to study atomic vibrations and dynamics, currently done with synchrotron radiation at a few high energy third generation facilities. It finds a wide range of applications in condensed matter physics, materials science, chemistry, biophysics, geosciences, and high-pressure researches. Many atomic dynamics and lattice thermodynamics information can be derived from NRIXS measurements. Phonon Density of States (DOS) characterizes lattice dynamics of a material and can be derived under the quasi-harmonic approximation. Combined with modeling and simulations, results from NRIXS can provide unique and clarifying insights into many fields of research. As for a spectroscopic technique, in order to be able to provide reliable information, close attention should be paid to many issues during experiments and data analysis afterwards. Here we discuss several issues relevant to its data analysis, namely, those of multiple sites, background treatments, and error estimates for some derived quantities.

show abstract

Experimental and theoretical studies of vibrational density of states inFe3O4single-crystalline thin films

Cited by 41 publications

References 58 publications

Origin of the Verwey transition in magnetite: Group theory, electronic structure, and lattice dynamics study

Origin of the Verwey transition in magnetite: Group theory, electronic structure, and lattice dynamics study

Electronic states of magnetite from photoemission spectroscopy ARUPS

Some notes on data analysis for nuclear resonant inelastic x-ray scattering

Contact Info

Product

Resources

About