Resonant photoemission at the L3 absorption edge of Mn and Ti and the electronic structure of 1T-Mn0.2TiSe2

The bonding situation for MnxTiSeis found to be stand out from that in non-Mn intercalated TMxTiSedue to large ionic contribution to the chemical bonding between the intercalated Mn and the host lattice.
M.V. Yablonskikh Phys.: Condens. Matter 24, 045504 (2012)

Layered dichalcogenides of Ti intercalated with transition metals TMxTiZ2 (TM—transition metal, Z = S, Se, Te) are promising materials for the creation of monatomic layers of magnetic metals with a given density where these layers are separated by nonmagnetic slabs of the TiZ2 matrix. Although many basic physical and chemical properties of TiZ2 dichalcogenides are defined by the chemical type of the chalcogenide element Z and its interaction with Ti, the most interesting changes in the physics and chemistry take place in TMx TiZ2 compounds. TMx TiZ2 intercalates are of fundamental scientific interest because of the formation of magnetic phase transitions and the formation of charge density waves (CDWs). The discovery of CDW to superconductive state transition in TiSe2 intercalated with copper and the expectation of such a transition in TiSe2 intercalated with iron and chromium along with emerging

progress in synthesis of single crystals of TMxTiZ2 and the expected dependences of their physical properties both on the type of intercalated TM and its concentration x have inspired a growing number of studies of the electronic structure of these compounds.

The only exception in the whole family of TMxTiZ2 is the MnxTiSe2 branch which exhibits both growth of conductivity and anomalously high increment of the Pauli contribution to the magnetic susceptibility when compared with the other TMxTiZ2 compounds. First, the magnitude of the lattice constant c0 is the largest amongst both TiSe2 and TiSe2 intercalated with Co or Cr. Second, the hybridization between Mn and the TiSe2 lattice is assumed to be of the lowest magnitude in the whole line of TMxTiZ2 . Third, the effective magnetic moment of Mn in MnxTiSe2 is found to be of higher magnitude than those of other TMs in TMx TiZ2 . These interesting results are reported for Mnx TiSe2 compounds where the Mn concentration x ≤ 0.2. It is also expected that the bonding situation in MnxTiSe2 will be quite outstanding from that in non-Mn TMxTiSe2 compounds.

In MnxTiSecompounds the chemical bonding between the host lattice and the Mn atoms in the octahedral surroundings is found to be of mixed ionic–covalent nature. These results are confirmed by the atomic multiplet calculations of the Ti and Mn LXAS and the Mn 2p XPS. According to the experimental data electrons are transferred from the manganese ions to the conduction band formed by the Ti 3d states.



The Ti 3d and Mn 3d bands of mixed orbital symmetry have been observed at a binding energy just below the Fermi level in the ResPES of the valence band. The E(k) band structure calculations performed suggest that the Ti 3d states are localized in the vicinity of the point Gamma of the Brillouin zone of the crystal. The Mn 3d states are localized along the direction K–Gamma–M.


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Resonant photoemission at the L3 absorption edge of Mn and Ti and the electronic structure of 1T-Mn0.2TiSe2

M. V. Yablonskikh, A. S. Shkvarin, Y. M. Yarmoshenko, N. A. Skorikov and A. N. Titov
J. Phys.: Condens. Matter 24, 045504 2012





Last Updated on Tuesday, 20 November 2012 12:13