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1993

Peter Dowben Publications

Articles 1 - 5 of 5

Full-Text Articles in Physics

The Structural Homogeneity Of Boron Carbide Thin Films Fabricated Using Plasma-Enhanced Chemical Vapor Deposition From B5H9+Ch4, Sunwoo Lee, J. Mazurowski, W.L. O'Brien, Q.Y. Dong, J.J. Jia, T.A. Callcott, K.E. Miyano, D.L. Ederer, D.R. Mueller, Peter A. Dowben Dec 1993

The Structural Homogeneity Of Boron Carbide Thin Films Fabricated Using Plasma-Enhanced Chemical Vapor Deposition From B5H9+Ch4, Sunwoo Lee, J. Mazurowski, W.L. O'Brien, Q.Y. Dong, J.J. Jia, T.A. Callcott, K.E. Miyano, D.L. Ederer, D.R. Mueller, Peter A. Dowben

Peter Dowben Publications

Boron carbide thin films of several B/C ratios have been deposited on Si(111) using plasma-enhanced chemical vapor deposition from nido-pentaborane(9) (B5H9) and methane (CH4). X-ray diffraction studies of boron carbide thin films on Si(111) exhibited characteristic microcrystalline diffraction lines. Soft x-ray emission spectroscopy was used to verify that the local electronic structure and composition of each sample corresponded to a homogeneous solid solution boron carbide phase.


Altering The Gd(0001) Surface Electronic Structure With Hydrogen Adsorption, Dongqi Li, Jiandi Zhang, Peter A. Dowben, M. Onellion Aug 1993

Altering The Gd(0001) Surface Electronic Structure With Hydrogen Adsorption, Dongqi Li, Jiandi Zhang, Peter A. Dowben, M. Onellion

Peter Dowben Publications

Hydrogen adsorption on Gd(0001) has been studied with angle-resolved photoemission. Hydrogen adsorption attenuates the surface state near EF on the clean Gd(0001) surfaces and induces two two-dimensional bands which are at 3.8 eV and about 6 eV near Γ¯. The state with the smaller binding energy has dz2 character at Γ¯ and disperses away from EF about 1 eV. The state at the greater binding energy disperses toward EF about 0.5–1 eV. At low substrate temperatures (120–130 K), the hydrogen chemisorption on the Gd(0001) surface results in a work-function decrease ...


Experimental Determination Of The Unoccupied Bands Of W(110), Dongqi Li, Peter A. Dowben, J.E. Ortega, F.J. Himpsel May 1993

Experimental Determination Of The Unoccupied Bands Of W(110), Dongqi Li, Peter A. Dowben, J.E. Ortega, F.J. Himpsel

Peter Dowben Publications

Inverse photoemission from W(110) has been used to determine the dispersion of the unoccupied energy bands along the tungsten ΓΣN line. The critical points are determined to be Γ12 at 2.6 eV, N1 at 2.2 eV, and the lower limit of N4 at 3.2 eV. The upper bound of the lifetime broadening is estimated as 0.3-0.4 eV at 2-3 eV above EF. The image state is observed at 4.5 eV above EF, or 0.7 eV in binding energy, relative to the vacuum level.


Canted Magnetic Moments At The Gd(0001) Surface, Dongqi Li, Jiandi Zhang, Peter A. Dowben, K. Garrison, P.D. Johnson, H. Tang, T.G. Walker, H. Hopster, J.C. Scott, D. Weller, D.P. Pappas May 1993

Canted Magnetic Moments At The Gd(0001) Surface, Dongqi Li, Jiandi Zhang, Peter A. Dowben, K. Garrison, P.D. Johnson, H. Tang, T.G. Walker, H. Hopster, J.C. Scott, D. Weller, D.P. Pappas

Peter Dowben Publications

With spin polarized electron spectroscopies, we have investigated ordered GD(0001) films deposited on W(110). The photoemission features of the gadolinium 5d surface state, the 4f levels, and the background exhibit considerable spin polarization along the same direction in the plane of the film, indicative of ferromagnetic coupling between the surface and the bulk. The 4f spin polarized photoemission data provides strong evidence that the surface 4f polarization differs from the bulk 4f polarization for Gd(0001). Our temperature dependent measurements with spin polarized secondary electron spectroscopy conclusively establishes that the surface of clean Gd(0001) possesses a perpendicular ...


Multiplet Fine Structure In The Photoemission Of The Gadolinium And Terbium 5p Levels, B.T. Thole, X.D. Wang, B.N. Harmon, Dongqi Li, Peter A. Dowben Apr 1993

Multiplet Fine Structure In The Photoemission Of The Gadolinium And Terbium 5p Levels, B.T. Thole, X.D. Wang, B.N. Harmon, Dongqi Li, Peter A. Dowben

Peter Dowben Publications

Fine structure is observed in the photoemission of the gadolinium and terbium 5p levels. The 5p levels are split into multiplets due to spin-orbit splitting and to Coulomb and exchange interactions with the f shell. The calculated theoretical spectra are in good agreement with the experimental results.