Resonant photoemission at the absorption edge of Mn and Ti and electronic structure of 1T-Mn0.2_{0.2}TiSe2_2

Resonant valence-band X-ray photoelectron spectra (ResPES) excited near 2p$_{3/2}$ core level energies, 2p X-ray photoelectron spectra (XPS) and L$_{3,2}$ X-ray absorption spectra (XAS) of Ti and Mn in single crystal of 1T-Mn$_2$TiSe$_2$ were studied for the first time. The ionic-covalent character of bonds formed by Mn atoms with the neighboring Se atoms in the octahedral coordination is established. From the XPS and XAS measurements compared with results of atomic multiplet calculations of Ti and Mn L$_{3,2}$ XAS it is found that Ti atoms are in ionic state of 4+ and Mn atoms are in the state of 2+. In ResPES of Mn$_{0.2}$TiSe$_2$ excited near Ti 2p$_{3/2}$ and Mn 2p$_{3/2}$ absorption edges the Ti 3d and Mn 3d bands at binding energies just below the Fermi level are observed. According to band structure calculations E$(\textbf{k})$ the Ti 3d states are localized in the vicinity of $\mathsf{\Gamma}$ point and the Mn 3d states are localized along the direction K-$\mathsf{\Gamma}$-M in the Brillouin zone of the crystal.Comment: 18 pages (preprint), 9 figure

Observing of Ti, Cr and Mn 2p-3d resonance in valence band of titanium dichalcogenides

Ti, Mn, Cr 2p-3d resonant photoemission for compounds with substitution of Ti atoms of host lattice by the Cr atoms CrxTi1-xSe2 and for compounds with intercalation of Mn and Cr atoms MnxTiSe2, CrxTiTe2 is studied. It is shown that the resonant behaviour depends on the geometry of survey, on 3d metal atoms lattice positions and on the magnitude and localization of atomic magnetic moment. © Published under licence by IOP Publishing Ltd

Localization of charge carriers in layered crystals MexTiSe 2 (Me = Cr, Mn, Cu) studied by the resonant photoemission

The probability of charge transfer in layered titanium diselenide between monolayers containing Cr, Mn, and Cu with different concentrations and host lattice TiSe2 is estimated according to the resonant photoemission data. For this purpose, the Raman-Auger contributions and narrow bands just below the Fermi energy were separated in the valence band spectra. These contributions provide the information about charge transfer. It is shown that the localization of the 3d electrons is typical for Cr and Cu atoms and strongly depends on theirs concentration. In MnxTiSe2, Mn 3d electrons are delocalized and the probability of the charge transfer is the greatest as compared with other compounds under investigation. © 2013 AIP Publishing LLC

Non-quasiparticle states in the core level spectra of ferromagnetic semiconductors and half-metallic ferromagnets

The Green's functions that determine x-ray spectra are calculated in the s-d exchange model of a saturated conducting ferromagnet in the presence of the core hole. A possibility to observe non-quasiparticle (NQP) states in the core level (x-ray absorption, emission and photoelectron) spectroscopy is demonstrated. It is shown that NQP contributions to resonant x-ray scattering spectra can be considerably enhanced by core hole effects in comparison with those to the density of states.Comment: 13 pages, 7 figures, final versio

The electronic structure formation of CuxTiSe2 in a wide range (0.04 < x < 0.8) of copper concentration

An experimental study of the electronic structure of copper intercalated titanium dichalcogenides in a wide range of copper concentrations (x = 0.05 - 0.6) using the x-rays photoemission spectroscopy, resonant photoemission and x-rays absorption spectroscopy has been performed. Negative energy shifts of the Ti 2p and Se 3d core levels spectra and a corresponding decrease of the photon energy in Ti 2p absorption spectra with increasing concentration of copper have been found. Such sign-anomalous shifts may be explained by the shielding effect of the corresponding atomic shells as a result of the dynamic charge transfer during the formation of a covalent chemical bond between the copper atoms and the TiSe2 matrix.Comment: 12 pages, 6 figure

Electronic Structure of CoxTiSe2 and CrxTiSe2

The results of investigations of intercalated compounds CrxTiSe2 and CoxTiSe2 by x-ray photoelectron spectroscopy and x-ray emission spectroscopy are presented. The data obtained are compared with theoretical results of spin-polarized band-structure calculations. A good agreement between theoretical and experimental data for the electronic structure of the investigated materials has been observed. The interplay between the M 3d−Ti3d hybridization (M=Cr, Co) and the magnetic moment at the M site is discussed. A 0.9-eV large splitting of the core Cr2p3/2 level was observed, which reveals a strong exchange magnetic interaction of 3d−2p electrons of Cr. In the case of a strong localization of the Cr 3d electrons (for x&lt;0.25), the broadening of the Cr L spectra into the region of the states above the nominal Fermi level was observed and attributed to x-ray reemission. The measured kinetic properties are in good accordance with spectral investigations and band calculation results. © 2001 The American Physical Society.This work was supported by the Russian Science Foundation for Fundamental Research (Projects No. 99-03-32503 and No. 00-15-96575), a NATO Linkage Grant (No. HTECH.LG 971222), and a DFG-RFFI Project. Financial support from the Deutsche Forschungsgemeinschaft is greatly acknowledged