Direct evidence of band modification and suppression of superstructure in TiSe2 upon Fe intercalation : An angle-resolved photoemission study

Cui Xiaoyu

Negishi Hiroshi

Titova S. G.

Shimada Kenya

Ohnishi Akimasa

Higashiguchi Mitsuharu

Miura Yuichi

Hino S.

Jahir A. M.

Titov A.

Bidadi H.

Negishi Saiko

Namatame Hirofumi

Taniguchi Masaki

Sasaki Minoru

Physical Review B - Condensed Matter and Materials Physics

We present electrical resistivity (ρ) measurements for the intercalation compound Fex TiSe2 (0≤x<0.16) over the temperature range from 4.2 to 300 K, and angle-resolved photoemission spectra for x=0, 0.05, and 0.14 at 50 and 250 K (or 280 K). At 250 K, TiSe2 is a semimetal having hole pockets centered at the Γ point and electron pockets around the L points of the Brillouin zone. Upon intercalation, Fe-derived flat bands appear just below the Fermi energy, and the Se 4p derived bands forming hole pockets at the Γ point are lowered. At 50 K, band folding due to 2a×2a×2c superlattice is observed clearly near the L point for the host and x=0.05, while it vanishes for x=0.14, consistent with the ρ-T data. The critical concentration for the suppression of the superstructure (0.05< xc ≤0.075) can be explained reasonably well by the percolation threshold of a two-dimensional-trianglar lattice consisting of seven Ti atoms, which is estimated to 1 14 (=0.0714).

iron

titanium compounds

photoelectron spectra

electrical resistivity

intercalation compounds

Brillouin zones

Fermi level

eng

American Physical Society

Copyright (c) 2006 The American Physical Society.

[ISSN] 0163-1829

[DOI] 10.1103/PhysRevB.73.085111

[NCID] AA11187113

[DOI] http://dx.doi.org/10.1103/PhysRevB.73.085111