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Physics & Astronomy

Department Information

Peter A. Dowben

Charles Bessey Professor, Physics & Astronomy/         
Nebraska Center for Materials and Nanoscience

E-mail: PDOWBEN1@unl.edu
Fax: (402) 472-2879
Office: 255 Behlen
Phone: (402) 472-9838

Biographical Summary
Research
Interests and Capabilities
Research Projects
Other Links
Publication Record
Recent Results and Key References
Graduate Students (and current affiliations)
Post-doc's (and current affiliations)

 

Biographical Summary:

2002 - present: Charles Bessey Professor, University of Nebraska
1995 - present: Professor of Physics and Graduate Fellow, University of Nebraska
1994 - present: Research Professor of Chemistry, University of Nebraska
1993 - 1995: Associate Prof. of Physics and Graduate Fellow, University of Nebraska
1990 - 1993: Associate Prof. of Physics, Syracuse University, Syracuse, New York
1987 - 1996: Adjunct Prof. of Chemistry, Syracuse University,
1986 - 1993: Member of Solid State Science and Technology Program, Syracuse
    University
1984 - 1990: Assistant Prof. of Physics, Syracuse University
1981 - 1983: Scientist with the Fritz-Haber Institut der Max-Planck-Gesellschaft, FRG
1981 - Visiting Scientist to the Department of Physics, University Osnabrueck, FRG
1980 - 1981: Research Assistant to Dr. M. Grunze, Fritz-Haber Institut der Max-Planck
    Gesellschaft, and the Free University, Berlin, FRG
1981 - Ph.D. in Physics, Cambridge University



Research:

Group Personnel

Juan Colon-Santana
Keisuke Fukutani
Ihor Ketsman
Jing Liu
Brad Nordell
Ning Wu
Jie Xiao
ZhengZheng Zhang

 Collaborators at UNL

Kirill Belashchenko (Physics)
Christian Binek (Physics)
Jennifer Brand (Engineering)
Barry Cheung (Chemistry)
Axel Enders (Physics)
Alexei Gruverman (Physics)
Yaroslov Losovyj (Physics)
Wai-Ning Mei (Physics)
Renat Sabirianov (Physics
R. Skomski (Physics)
Andre Sokolov (Physics)
James Takacs (Chemistry)
Evgeny Tsymbal (Physics)


Interests and Capabilities:

The major focus of the Dowben group emphasizes the changes in electronic (band) structure across electronic phase transitions in reduced dimensionality. Of interest are ferromagnetism in local moment systems or spatially restricted systems, ferroelectricity and the nonmetal to metal transition.

Specific techniques include angle-resolved photoemission, resonant photoemission, inverse photoemission and spin polarized inverse photoemission. Other techniques include spin polarized photoemission, characteristic energy loss, low energy electron diffraction, angle resolved thermal desorption spectroscopy, X-ray photoemission, and Magneto-optic Kerr effect.

 

Research Projects:

(1) Organic and Photolytic organometallic chemical vapor deposition of materials in ultrahigh vacuum for spin valves and spin-tunnel junctions.

(2) Orientation, bonding and electronic structure of organic overlayers, organometallic molecular overlayers and molecular magnets.

(3) The temperature dependent electronic structure of ferroelectric crystalline molecular films, as a function of metallicity.

(4) The spin polarized occupied and unoccupied band structure of local moment ferromagnetic systems as a function of temperature.

Funded by the NSF-Chem., NSF Quantum and Spin MRSEC (DMR-0213808), Office of Naval Research, the Defense Threat Reduction Agency and the Nebraska Research Initiative



Other Links:

Surface Science:
www.chem.qmw.ac.uk/surfaces/
www.vacuum.org
www.iap.tuwein.ac.at/~werner/data.html
www.lasurface.com/accueil/index.php

Nanodots and Clusters:
(Ward Plummer) www.phys.utk.edu/WPWebSite/ewp_main.htm
http://cluster-science.net/service.php
www.salford.ac.uk/chemist/nmbres.html
www.cnms.ornl.gov/
www.mrsec.unl.edu

Synchrotron Light Sources:
(SRC) www.src.wisc.edu/
(CAMD) www.camd.lsu.edu/
(NSLS) www.nsls.bnl.gov/
(BESSY) www.bessy.de/

Rare Earth Magnetism:
www.wspc.com.sg/books/physics/3851.html
(Berlin) orion.physik.hu-Berlin.de

Boron Carbide Neutron Detectors:
http://www.amazings.com/ciencia/noticias/300702b.html
http://www.engr.unl.edu/FINDER/research/index.htm



Publication Record:

Author of more than 400 articles in refereed journals and books, 24 invited review articles, 23 invited presentations at national and international conferences, and 14 patents. Some papers may be found on the digital commons: http://digitalcommons.unl.edu/physicsdowben

 

Recent Results and Key References:

Limits to Half Metallic Ferromagnetism:

P.A. Dowben, J. Phys. Cond. Matter 19 (2007) 31031, and the papers that follow in that issue of JPCM

R. Skomski and P.A. Dowben, "Intra-Atomic Aspects of Magnon-Plasmon Interactions", J. Appl. Phys. 99 (2006), 08F508

P.A. Dowben and S.J. Jenkins. "The Limits to Spin-Polarization in Finite-Temperature Half- Metallic Ferromagnets", in Frontiers in Magnetic Materials, edited by Anant Narlikar, Springer Verlag (2005)

R. Skomski and P. A. Dowben, "The Finite-Temperature Densities of States for Half-Metallic Ferromagnets", Europhysics Letters 58 (2002) 544-548

P.A. Dowben and R. Skomski, "Are Half-Metallic Ferromagnets Half-Metals? (invited)", Journal of Applied Physics 95 (2004) 7453-7458

Electronic Phase Transitions in Molecular Systems:

Jie Xiao, Andrei Sokolov, P.A. Dowben, "Changing Band Offsets in Copper-Phthalocyanine to Copolymer Poly(vinylidene fluoride with trifluoroethylene) Heterojunctions", Appl. Phys. Lett. 90 (2007) 242907

D.-Q. Feng, D. Wisbey, Y. Tai, Ya. B. Losovyj, M. Zharnikov and P.A. Dowben, "Abnormal Temperature Dependence of Photoemission Intensity Mediated by Thermally Driven Reorientation of a Monomolecular Film", J. Phys Chem. B 110 (2006) 1095-1098 155411

P.A. Jacobson, Luis G. Rosa, C.M. Othon, Kristin Kraemer, A.V. Sorokin, Stephen Ducharme, and P.A. Dowben, "Water Absorption and Dielectric Changes in Crystalline Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymers Films", Applied Physics Letters 84 (2004) 88-90

Hongwei Qu, Wei Yao, T. Garcia, Jiandi Zhang, A.V. Sorokin, S. Ducharme, P.A. Dowben, V.M. Fridkin, "Nanoscale Polarization Manipulation and Conductance Switching in Ultra-Thin Ferroelectric Copolymer Films: P(VDF-TrFE)", Appl. Phys. Lett. 82 (2003) 4322

Bo Xu, Jaewu Choi, A.N. Caruso and P.A. Dowben, "Band Filling and Depletion Through the Doping of Polyaniline Thin Films", Applied Physics Letters 80 (2002) 4342-4344

Defect Mediated Coupling in Magnetic Tunnel Junction Structures:

J.P. Velev, P.A. Dowben, E.Y. Tsymbal, S.J. Jenkins and A.N. Caruso, "Interface Effects in Spin-Polarized Metal/Insulator Layered Structures", Surface Science Reports 63 (2008) 400-425.

P.A. Dowben and B. Doudin, "On the Importance of Defects in Magnetic Tunnel Junctions", Lecture Notes in Physics vol. 678, Springer Verlag (2005) 309-326

L. Bernard, J. Monson, A. Sokolov, Zong-Yuan Liu, C.-S. Yang, P.A. Dowben, B. Doudin, A. Harken, P. Welsch and B.W. Robertson, "Magnetoresistance in Boron Carbide Junctions", Appl. Phys. Lett. 83 (2003) 3743-3745

Ruihua Cheng, A.N. Caruso, L. Yuan, S.-H. Liou, and P.A. Dowben, "Magnetic Coupling in Co/Cr2O3/CrO2 "Trilayer" Films", Applied Physics Letters 82 (2003) 1443-1445

Ya.B. Losovyj, I.N. Yakovkin, S.D. Barrett, Takashi Komesu, and P.A. Dowben, "Evidence of Possible Band Symmetry Effects in STM Studies of Gd Overlayers", Surface Science 520 (2002) 43-52

A. Sokolov, C.-S. Yang, L. Yuan, S.-H. Liou, Ruihua Cheng, H.-K. Jeong, T. Komesu, B. Xu, C.N. Borca, P.A. Dowben and B. Doudin, "Zero-Bias Anomaly in CrO2 Junctions", Europhys. Letters 58 (2002) 448-454

Recent General Papers on the Nometal to Metal Transition:

Chun-gang Duan, R.F. Sabiryanov, Jianjun Liu, W.N. Mei, P.A. Dowben and J.R. Hardy, "Strain Induced Half Metal to Semiconductor Transition in GdN", Physical Review Letters 94 (2005) 237201

Ya.B. Losovyj, I.N. Yakovkin, Hae-Kyung Jeong, David Wisbey, and P.A. Dowben, "Lattice-Stiffening Transition in Gadolinium Chains on Furrowed (112) Surfaces", J. Phys. Cond. Matter. 16 (2004) 4711-4724

C. N. Borca, Bo Xu, Takashi Komesu, Hae-Kyung Jeong, M.T. Liu, S.-H. Liou, S. Stadler, Y. Idzerda and P.A. Dowben, "Electronic Structure Modifications Induced by Surface Segregation in La0.65Pb0.35MnO3", Europhysics Letters 56 (2001) 722-728

P.A. Dowben, "The Metallicity of Thin Films and Overlayers", Surface Science Reports 40 (6-8) (2000) 151-247

 

Graduate Students (and current affiliations):

NAME Degree Date Current Affiliation
Daniel C. Driscoll Ph.D. 1987 Naval Surface Warfare Center, Virginia
Hans-Jorg Ruppender Dipl. Chem. 1987 CEO Dentech, Kaiserslautern, FRG
Greg T. Stauf Ph.D. 1988 Formerly, Advanced Technology Materials Inc., Connecticut, now laid off.
Sangramitra Baral M. Sc. 1990 NRL
Shikha Varma Ph.D. 1990 Associate Professor of Physics, Institute of Physics, Bhubaneswar, India
David LaGraffe Ph.D. 1990 Deputy Office Director, NA-221, Lt. Col. (Army)
National Nuclear Security Administration
Yolanda Kime Ph.D. 1991 S.U.N.Y-Cortland, Professor Emeritus
John Mazurowski M.Sc. 1992 Senior Engineer, Pennsylvania State Univ. Electro-Optic Cntr. http://www.electro-optics.org
Yoon-Gi Kim Ph.D. 1992 Samsung Electronics, South Korea
Sunwoo Lee Ph.D. 1992 Patent Law, Washington D.C.
Dongqi Li Ph.D. 1993 On disability leave
Jiandi Zhang Ph.D. 1994 Professor of Physics, Louisiana State University
NSF Highlight
Dongjin Byun Ph.D. 1995 Professor, Dept. of Materials Science and Engineering, Korea University
Seong-Don Hwang Ph.D. 1996 Patent Lawyer, Chicago
John Kushneir III M.Sc. 1996 Leybold-Inficon, East Syracuse
Tara Jean McAvoy M.Sc. 1997 Process Engineer with Raytheon, California
Dulip Welipitiya Ph.D. 1997 Hitachi Global Storage, San Jose, CA
Carlo Waldfried Ph.D. 1998 Axcelis
Jaewu Choi Ph.D. 1998 Associate Professor, Dept. of Information Display, Kyung Hee University, Korea
Delia Ristoiu Ph.D. 2000 ST-Microelectronics, Grenoble, France
Hanni Dulli Ph.D. 2000 Assistant Professor of Physics, Oman Medical College, Muscat, Oman
Camelia Borca Ph.D. 2001 Staff, Paul Scherrer Institute
Laeticia Bernard Diplom Physiker 2002 Post-doc at Yale
Rui-Hua Cheng Ph.D. 2002 Assistant Professor, Indiana University - Purdue - Indianapolis
Takashi Komesu Ph.D. 2002 Staff, Spring 8, Japan
Bo Xu Ph.D. 2002 Assistant Professor of Physics, Yanjing University
Hae-Kyung Jeong Ph.D. 2003 Research Professor, Sungkyunkwan University
Anthony Caruso Ph.D. 2004 Assistant Professor, Univ. of Missouri - Kansas City
Luis Rosa Ph.D. 2005 Assistant Professor of Physics, University of Puerto Rico - Humacao
Snow Balaz M.Sc. 2005
(Ph.D. in Engineering with J. Brand, 2007)		 Post-doc., Department of Physics, University of California - Riverside
Danqin Feng Ph.D. 2007 Post-doc., Department of Physics, University of California, Santa Barbara
Carolina Ilie Ph.D. 2008 Assistant Professor of Physics, S.U.N.Y. - Oswego
David Wisbey Ph.D. 2008 Post-doc., NIST, Boulder, CO
Jie Xiao Ph.D. 2009 Post-doc., U. Nebraska
Ning Wu Ph.D. 2009 Post-doc., U. Nebraska




Post-doc's (and current affiliations):

NAME Date(s) Worked For Dowben Current Affiliation
David McIlroy 1993-1996 Professor of Physics, University of Idaho
Jiandi Zhang 1994-1995 Professor of Physics, Louisiana State University
NSF Highlight
Zhenchen Zhong 1997-1999 JQM Magnetic Systems, China
Jaewu Choi 1998-2001 Associate Professor, Dept. of Information Display, Kyung Hee University, Korea
Hae-Kyung Jeong 2003-2004 Research Prof., Sungkyunkwan University
Takashi Komesu 2007 Staff, Spring 8, Japan
Ihor Ketsman 2006 - present  
Jie Xiao 2009 - present  
Ning Wu 2009 - present