289 research outputs found
VO2: a two-fluid incoherent metal?
We present {\it ab initio} LDA+DMFT results for the many-particle density of
states of on the metallic side of the strongly first-order
(-driven) insulator-metal transition. In strong contrast to LDA predictions,
there is {\it no} remnant of even correlated Fermi liquid behavior in the
correlated metal. Excellent quantitative agreement with published photoemission
and X-ray absorption experiments is found in the metallic phase. We argue that
the absence of FL-quasiparticles provides a natural explanation for the
bad-metallic transport for . Based on this agreement, we propose
that the I-M transition in is an orbital-selective Mott transition,
and point out the relevance of orbital resolved one-electron and optical
spectroscopy to resolve this outstanding issue.Comment: 4 pages, 3 figure
X-ray fluorescence study of organic-inorganic polymer conversion into ceramics induced by ion irradiation
Magnetic properties of Chelyabinsk meteorite (15 February 2013) at high temperatures
Magnetic properties of the Chelyabinsk meteorite were studied in a wide temperature range - up to ∼ 1300 K. The analysis shows that the meteorite contains ferromagnetic inclusions of both Fe-Ni alloy and pure iron. It has visually been demonstrated that iron inclusions of the Chelyabinsk meteorite experience no β→γ structural phase transformation. © Published under licence by IOP Publishing Ltd.Russian Foundation for Basic Research, RFBR: 17-02-00005The research was carried out within the state assignment of Minobrnauki of Russia theme “Magnet” No.АААА-А18-118020290129-5, theme “Electron” No. АААА-А18-118020190098-5), theme “Spin” No. АААА-А18-118020290104-2 supported in part by RFBR (project No. 17-02-00005)
Stability of boron-doped graphene/copper interface: DFT, XPS and OSEE studies
Two different types of boron-doped graphene/copper interfaces synthesized
using two different flow rates of Ar through the bubbler containing the boron
source were studied. X-ray photoelectron spectra (XPS) and optically stimulated
electron emission (OSEE) measurements have demonstrated that boron-doped
graphene coating provides a high corrosion resistivity of Cu-substrate with the
light traces of the oxidation of carbon cover. The density functional theory
calculations suggest that for the case of substitutional (graphitic)
boron-defect only the oxidation near boron impurity is energetically favorable
and creation of the vacancies that can induce the oxidation of copper substrate
is energetically unfavorable. In the case of non-graphitic boron defects
oxidation of the area, a nearby impurity is metastable that not only prevent
oxidation but makes boron-doped graphene. Modeling of oxygen reduction reaction
demonstrates high catalytic performance of these materials.Comment: 15 pages, 8 figures, to appear in Appl. Surf. Sc
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