Electronic structure of the 3C-SiC(001)2 x 1 surface studied with angle-resolved photoelectron spectroscopy

被引:8
|
作者
Duda, L [1 ]
Johansson, LSO
Reihl, B
Yeom, HW
Hara, S
Yoshida, S
机构
[1] Univ Dortmund, D-44221 Dortmund, Germany
[2] Univ Tokyo, Res Ctr Spectrochem, Tokyo 113, Japan
[3] Electrotech Lab, Tsukuba, Ibaraki 305, Japan
关键词
angle-resolved photoemission; low index single crystal surfaces; silicon carbide; surface electronic phenomena;
D O I
10.1016/S0039-6028(99)00763-3
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We have investigated the electronic structure of the single-domain 3C-SiC(001)2 x 1 using angle-resolved photoemission and synchrotron radiation. Two different surface-state bands are clearly identified within the bulk bandgap. The upper band has a binding energy of 1.4 eV at the center of the surface Brillouin zone and shows a weak dispersion of 0.3 eV in the <(Gamma)over bar>-(J) over bar direction, but is non-dispersive in the perpendicular direction. It has a polarization dependence suggesting a p(z) character, as expected for a Si dangling-bond state. The second band is located at 2.4 eV binding energy and is non-dispersive. The Fermi level position was determined to be at 1.7 eV above the valence-band maximum in our experiment. The weak or non-existent dispersions suggest highly localized electronic states at the surface, which are consistent with the polarized nature of the Si-C bond. The measured dispersions were compared to calculated dispersions for the proposed models for both 2 x 1 and the c(4 x 2) reconstructions, because of the expected close similarity between the 2 x 1 and the c(4 x 2) structures. Our results are in poor agreement with calculated dispersions for the simple 2x1 model with one monolayer Si termination and the alternating up-and-down-dimer (AUDD) model for c(4 x 2). The theoretical dispersions for the recently proposed missing-row-asymmetric-dimer (MRAD) model for c(4 x 2) shows somewhat better agreement, although still with significant deviations. (C) 1999 Elsevier Science B.V. All rights reserved.
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页码:199 / 210
页数:12
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