Europhys. Lett.
Volume 67, Number 2, July 2004
Page(s) 240 - 246
Section Interdisciplinary physics and related areas of science and technology
Published online 01 July 2004
Europhys. Lett., 67 (2) , pp. 240-246 (2004)
DOI: 10.1209/epl/i2004-10052-6

Layer-dependent band dispersion and correlations using tunable soft X-ray ARPES

N. Kamakura1, Y. Takata1, T. Tokushima1, Y. Harada1, A. Chainani1, 2, K. Kobayashi3 and S. Shin1, 4

1  RIKEN, Harima Institute - 1-1-1 Kouto, Mikazuki, Sayo, Hyogo 679-5148, Japan
2  Institute for Plasma Research - Bhat, Gandhinagar 382 428, Gujarat, India
3  SPring-8/JASRI - Mikazuki, Hyogo 679-5198, Japan
4  Institute for Solid State Physics, University of Tokyo Kashiwanoha, Kashiwa, Chiba 277-8581, Japan

(Received 22 January 2004; accepted in final form 3 May 2004)

Soft X-ray Angle-Resolved Photoemission Spectroscopy is applied to study in-plane band dispersions of nickel as a function of probing depth. Photon energies between $h\nu=190$ and 780 $\un{eV}$ were used to effectively probe up to $\sim 3$-7 layers ( $\sim
5$ -12 $\un{\AA}$). The results show layer-dependent band dispersion of the $\Delta_{2\downarrow}$ minority spin band which crosses the Fermi level in 3 or more layers, in contrast to the known top 1-2 layers dispersion obtained using ultra-violet rays. The layer dependence corresponds to an increased value of exchange splitting and suggests reduced-correlation effects in the bulk compared to the surface.

71.20.Be - Transition metals and alloys.
79.60.-i - Photoemission and photoelectron spectra.
75.50.Cc - Other ferromagnetic metals and alloys.

© EDP Sciences 2004