Diluted magnetic semiconductors (DMS) are most interesting materials for spintronic application [1]due to s-p-d interaction of 3d electrons with the s-p valence electrons of the volume(3D)and surface(2D)of the crystal. Photoemission study of the valence band electronic structure for clean, freshly cleaved (110) relaxed 1x1 surface of ZnTe crystals and for these surface after sequentially deposited on it small and controlled amount of Mn atoms were performed. The crystalline samples of ZnTe was grown in the Institute of Physics, PAS in Warsaw and oriented as parallelepiped (10 x 5 x 5 mm³ )with the cleavage plane parallel to the 5 x 5 plane. The Flipper II beam line of the synchrotron radiation in HASYLAB was used. The clean surface of ZnTe (110) was obtained by the cleavage and LEED study shows the (1x1) patterns. The analysis of: constant initial state, energy distribution curves, Zn 3d and Te 4d core level spectra showed that at very low Mn coverage (< 0.15 nm) manganese interaction with ZnTe results in the creation of the Zn_1-xMn_xTe (110) surface ternary alloy. Further deposition of Mn atoms leads to the formation of the metallic manganese on the surface. The successive annealing leads to the diffusion of Mn atoms and to the formation of DMS at the surface region. The experimental results were compared to the calculated electronic band structure of Zn_1-xMn_xTe crystals.
This work was supported in part within: European Commission IHP-Contract HPRI-CT-1999-00040/2001- 00140; and KBN SPUB-M/DESY/P-03/DZ-213/2000;and European Community program G1MA-CT-2002-4017 (Center of Excellence CEPHEUS).
[1]. T. Dietl, Physica E 10, 120 (2001)