Band Gap and Electronic structure of an Epitaxial, Semiconducting Cr0.80Al0.20 Thin Film
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Boekelheide, Z.; Gray, A. X.; Papp, C.; Balke, B.; Stewart, D. A.; Ueda, S.; Kobayashi, K.; Hellman, F.; Fadley, C. S.
Cr(1-x)Alx exhibits semiconducting behavior for x=0.15-0.26. This Letter uses hard x-ray photoemission spectroscopy and density functional theory to further understand the semiconducting behavior. Photoemission measurements of an epitaxial Cr0.80Al0.20 thin film show several features in the band region, including a gap at the Fermi energy (Ef) for which the valence band edge is 95 +- 14 meV below Ef. Theory agrees well with the valence band measurements, and shows an incomplete gap at Ef due to the hole band at M shifting almost below Ef.
This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and the Nanotechnology Network Project, MEXT, Japan. C. Papp and B. Balke thank the Humboldt foundation for support. Calculations were done at the Cornell Nanoscale Facility, part of the National Nanotechnology Infrastructure Network (NNIN) funded by NSF. HXPS experiments were approved at the NIMS Beamline Station (Proposal No. 2009A4906)
American Physical Society
alloy; chromium; aluminum; electronic structure; photoemission; density functional theory; CrAl; band gap
Previously Published As
Z. Boekelheide, A. X. Gray, C. Papp, B. Balke, D. A. Stewart, S. Ueda, K. Kobayashi, F. Hellman, and C. S. Fadley, Physical Review Letters, 105, 236404 (2010)