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Full-Text Articles in Physics
The Anisotropic Band Structure Of Layered In4Se3(001), Yaroslav B. Losovyj, L. Makinistian, E. A. Albanesi, A. G. Pethukov, Jing Liu, P. Galiy, O. R. Dveriy, Peter A. Dowben
The Anisotropic Band Structure Of Layered In4Se3(001), Yaroslav B. Losovyj, L. Makinistian, E. A. Albanesi, A. G. Pethukov, Jing Liu, P. Galiy, O. R. Dveriy, Peter A. Dowben
Peter Dowben Publications
There is discernable and significant band dispersion along both high symmetry directions for cleaved ordered surfaces of the layered In4Se3(001). The extent of dispersion of approximately 1 eV is observed along the surface chain rows, and about 0.5 eV perpendicular to the surface “furrows,” consistent with theoretical expectations. A possible surface state exists at the surface Brillouin zone edge, in the direction perpendicular to the chains, in a gap of the projected bulk band structure. Excluding the possible surface state, the experimental hole mass is 5.5 times greater along the chains than perpendicular to the chains, …
The Kinetic Energy Dependent Effective Debye Temperature For Cos2 (100), Ning Wu, David Wisbey, Takashi Komesu, Z. X. Yu, M. Manno, L. Wang, C. Leighton, Peter A. Dowben
The Kinetic Energy Dependent Effective Debye Temperature For Cos2 (100), Ning Wu, David Wisbey, Takashi Komesu, Z. X. Yu, M. Manno, L. Wang, C. Leighton, Peter A. Dowben
Peter Dowben Publications
The effective Debye temperatures of the highly spin-polarized material CoS2 were measured using temperature dependent low energy electron diffraction and shown to be dependent upon electron kinetic energy. The normal dynamic motion of the (100) surface results in the effective surface Debye temperature of 326 ± 9 compared to a bulk Debye temperature of 612 ± 24 K. Similar values for the bulk Debye temperature have been obtained through LEED I(V) analysis and core level photoemission with a lower value for the bulk Debye temperature found from heat capacity measurements.
The Local Environment Of Co In B5ChX, Peter A. Dowben, A. Yu. Ignatov, Jing Lui, Ralph Skomski
The Local Environment Of Co In B5ChX, Peter A. Dowben, A. Yu. Ignatov, Jing Lui, Ralph Skomski
Peter Dowben Publications
Cobalt-doped boron carbides produced by simultaneous plasma-enhanced chemical vapor deposition of carborane and cobaltocene are investigated. Cobalt does not dope plasma-enhanced chemical vapor deposition grown boron carbides as a random fragment of the cobaltocene source gas. The Co atoms are fivefold boron coordinated (R=2.1 Å) and chemically bonded to the icosahedral cages of B10CHx or B9C2Hy. Pairwise Co doping occurs with the cobalt atoms favoring sites about 5.3 Å apart. The cobalt strongly hybridizes with the molecular orbitals of the icosahedral cage, and the states in the region of the band …
The Bulk Band Structure And Inner Potential Of Layered In4Se3, Jing Liu, Yaroslav B. Losovyj, Takashi Komesu, Peter A. Dowben, L. Makinistian, E. A. Albinesi, A. G. Petukhov, P. Galiy, Ya. Fiyala
The Bulk Band Structure And Inner Potential Of Layered In4Se3, Jing Liu, Yaroslav B. Losovyj, Takashi Komesu, Peter A. Dowben, L. Makinistian, E. A. Albinesi, A. G. Petukhov, P. Galiy, Ya. Fiyala
Peter Dowben Publications
The layered In4Se3 system does have a bulk band structure (i.e. discernible and significant band dispersion) perpendicular to the cleavage plane. Band widths (the extent of dispersion) of 300 meV or more are observed, for In-p and Se-p weighted bands within the valence region, and is indicative of a bulk band structure. Two-dimensionality of state is clearly not conserved, and there must exist interactions between layers sufficient to support a bulk band structure.
Different Approaches To Adjusting Band Offsets At Intermolecular Interfaces, Peter A. Dowben, Jie Xiao, Bo Xu, Andrei Sokolov, Bernard Doudin
Different Approaches To Adjusting Band Offsets At Intermolecular Interfaces, Peter A. Dowben, Jie Xiao, Bo Xu, Andrei Sokolov, Bernard Doudin
Peter Dowben Publications
We show that at the hetero-molecular interface, the molecular band offsets can be modified by either adjusting the dopant or dopant concentration of one or both molecular layers or by changing the dipole orientation at the intermolecular interface. Photoemission studies reveal the changes in electronic structure and diode devices exhibit conduction properties that are altered in response to changes to the molecular band offsets. As a demonstration, thin film copper phthalocyanine to crystalline ferroelectric copolymer poly(vinylidene fluoride with trifluoroethylene) heterojunction diodes, without additional dopants, are compared with doped polyaniline layers on the crystalline ferroelectric copolymer poly(vinylidene fluoride with trifluoroethylene).
Gd-Doping Of Hfo2, Ihor Ketsman, Yaroslav B. Losovyj, Jinke Tang, Zhenjun Wang, M. L. Natta, Jennifer I. Brand, Peter A. Dowben
Gd-Doping Of Hfo2, Ihor Ketsman, Yaroslav B. Losovyj, Jinke Tang, Zhenjun Wang, M. L. Natta, Jennifer I. Brand, Peter A. Dowben
Peter Dowben Publications
An increase in the density of states between the oxygen 2p bands and the Fermi level is seen with increasing Gd concentrations. In addition, for the Gd-doped HfO2 films, the Gd 4f photoexcitation peak at 5.5 eV below the valence band maximum was identified using resonant photoemission. Electrical measurements show pronounced rectification properties for lightly-doped Gd:HfO2 films on p-Si and for heavily-doped Gd:HfO2 films on n-Si, suggesting a crossover from n-type to p-type behavior with increasing doping level. In addition, there is an increase in the reverse bias current with neutron irradiation.
The Gold And Oxygen (3 × 1) Structures On W(1 1 2), Ihor Ketsman, N. Lozova, John Scott, Peter A. Dowben, I. N. Yakovin, S. M. Zuber
The Gold And Oxygen (3 × 1) Structures On W(1 1 2), Ihor Ketsman, N. Lozova, John Scott, Peter A. Dowben, I. N. Yakovin, S. M. Zuber
Peter Dowben Publications
The adsorption of two very different adsorbates, gold and oxygen, induce the formation of a (3 × 1) surface structure on both W(1 1 2) and Mo(1 1 2). In spite of similar adsorbate unit cells, the surface electronic structure, derived from photoemission, exhibits pronounced differences for the two adsorbates. Indeed, both experiment and simulations indicate substantial changes in electronic structures of (1 × 1) and (3 × 1) gold overlayers supported by highly anisotropic (1 1 2) plane. We speculate that (3 × 1) is a favored periodicity in the atomic rearrangement of the (1 1 2) surfaces of …
Photofragmentation Of Closo-Carboranes Part 1: Energetics Of Decomposition, Danqin Feng, Jing Liu, Adam P. Hitchcock, A. L. David Kilcoyne, Tolek Tyliszczak, Norman F. Riehs, Eckart Rühl, John D. Bozek, David Mcilroy, Peter A. Dowben
Photofragmentation Of Closo-Carboranes Part 1: Energetics Of Decomposition, Danqin Feng, Jing Liu, Adam P. Hitchcock, A. L. David Kilcoyne, Tolek Tyliszczak, Norman F. Riehs, Eckart Rühl, John D. Bozek, David Mcilroy, Peter A. Dowben
Peter Dowben Publications
The ionic fragmentation following B 1s and C 1s excitation of three isomeric carborane cage compounds [closo-dicarbadodecaboranes: orthocarborane (1,2-C2B10H12), metacarborane (1,7-C2B10H12), and paracarborane (1,12-C2B10H12)] is compared with the energetics of decomposition. The fragmentation yields for all three molecules are quite similar. Thermodynamic cycles are constructed for neutral and ionic species in an attempt to systemically characterize single-ion closo-carborane creation and fragmentation processes. Lower energy decomposition processes are favored. Among the ionic species, the photon-induced decomposition is dominated by BH …
The Surface Stability Of Cos2(100), Ning Wu, Renat F. Sabirianov, Chun-Gang Duan, Wai-Ning Mei, David Wisbey, Yaroslav B. Losovyj, M. Manno, C. Leighton, En Cai, Jiandi Zhang, Peter A. Dowben
The Surface Stability Of Cos2(100), Ning Wu, Renat F. Sabirianov, Chun-Gang Duan, Wai-Ning Mei, David Wisbey, Yaroslav B. Losovyj, M. Manno, C. Leighton, En Cai, Jiandi Zhang, Peter A. Dowben
Peter Dowben Publications
The stability of various possible terminations of the CoS2 (1 × 1) surface have been explored and theoretical expectations are found to agree with experiment. With extensive annealing, there is a phase separation at the (100) surface of CoS2. Sulfur segregation to the surface leads to a significant change in the largely sulfur bands due to changes in the hybridized bands, with cobalt. Resonant photoemission spectra indicate clearly that the hybridized cobalt and sulfur bands, characteristic of the CoS2 bulk, lie at higher binding energies than those of segregated sulfur layers. This is discussed in terms …
The Kinetic Energy Dependent Effective Debye Temperature For Cos2 (100), Ning Wu, David Wisbey, Takashi Komesu, Z. X. Yu, M. Manno, L. Wang, C. Leighton, Peter A. Dowben
The Kinetic Energy Dependent Effective Debye Temperature For Cos2 (100), Ning Wu, David Wisbey, Takashi Komesu, Z. X. Yu, M. Manno, L. Wang, C. Leighton, Peter A. Dowben
Peter Dowben Publications
The effective Debye temperatures of the highly spin-polarized material CoS2 were measured using temperature dependent low energy electron diffraction and shown to be dependent upon electron kinetic energy. The normal dynamic motion of the (100) surface results in the effective surface Debye temperature of 326 ± 9 K compared to a bulk Debye temperature of 612 ± 24 K. Similar values for the bulk Debye temperature have been obtained through LEED I(V) analysis, core level photoemission with a lower value for the bulk Debye temperature found from heat capacity measurements.
Electronic Structure Evidence For All-Trans Poly(Methylvinylidene Cyanide), Jie Xiao, Matt Poulsen, D. Sahadeva Reddy, James M. Takacs, Yaroslav B. Losovyj, Peter A. Dowben
Electronic Structure Evidence For All-Trans Poly(Methylvinylidene Cyanide), Jie Xiao, Matt Poulsen, D. Sahadeva Reddy, James M. Takacs, Yaroslav B. Losovyj, Peter A. Dowben
Peter Dowben Publications
On the basis of a comparison of theoretical quantum calculations, by both semiempirical and ab initio methods, with photoemission and inverse photoemission results, we suggest that polymethylvinylidenecyanide (PMVC) adopts an all-trans conformation with few, if any, alternating trans-gauche carbon–carbon bond arrangements. The comparison of theory with the available photoemission and inverse photoemission excludes the presence of a significant fraction of gauche bonds in the polymer chains, indicative of the all-trans conformation, with dipoles all aligned.
Interface-Induced Spin And Dipole Ordering Of The Copper Spin ½ Molecule: Bis(4-Cyano-2,2,6,6-Tetramethyl-3,5-Heptanedionato)Copper(Ii), David Wisbey, Ning Wu, Danqin Feng, Anthony N. Caruso, John Belot, Yaroslav B. Losovyj, Elio Vescovo, Peter A. Dowben
Interface-Induced Spin And Dipole Ordering Of The Copper Spin ½ Molecule: Bis(4-Cyano-2,2,6,6-Tetramethyl-3,5-Heptanedionato)Copper(Ii), David Wisbey, Ning Wu, Danqin Feng, Anthony N. Caruso, John Belot, Yaroslav B. Losovyj, Elio Vescovo, Peter A. Dowben
Peter Dowben Publications
Using light-polarization-dependent angle-resolved photoemission, the metal-organic molecule bis(4-cyano- 2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) (or Cu(CNdpm)2, i.e., C24H36N2O4Cu, Cu(II)) is observed to adopt a preferential orientation that depends on the film thickness and substrate when adsorbed on Co(111) and Cu(111). In addition, the final-state binding energies change with film thickness, suggesting the substrates affect the screening or charging in the photoemission final state. For Cu(CNdpm)2 deposited on Co(111), the induced spin polarization was found to depend strongly on the molecular orbital contributions.