Physics of complex electron systems. Strongly correlated transition metal oxides (colossal magnetoresitive manganites, cuprate high temperature superconductors, cobalt oxides), Fe-based high temperature superconductors, binary oxides (VOx, V2O3, EuO, CrO).
Physics of novel materials and novel materials characterization methodology. Materials for energy storage (cobaltates, delafossites, co-doped TiO2) and technological applications such as sensors, electronics, displays (transparent conducting oxides).
Properties, growth and characterization of low dimensional materials, nanostructures, surfaces and interfaces in materials of technological relevance.
Light - matter interaction and physics of the fundamental processes concerning the use and development of soft-x-ray spectroscopies techniques.
High-resolution angle-resolved photoemission spectroscopy (ARPES), core level photoemission spectroscopy, x-ray absorption spectroscopy (XAS), soft x-ray emission spectroscopy (XES) and inelastic x-ray scattering (RIXS). Development of advanced scientific instrumentation for x-ray spectroscopies.
Atomic, electronic, magnetic and orbital dynamics in complex electron systems. Sub-picoseconds temporal dynamics of different degrees of freedom in complex electron systems. Phase transitions.
I obtained my Ph.D. in Physics in September 2003 from UC Davis (CA) with Prof. C. S. Fadley. Immediately after, I became a Postdoctoral Fellow at Stanford University (CA) with Prof. Z. X. Shen, with a joint appointment as a Visiting Scientist at the Advance Light Source (ALS) in Berkeley (CA) in the User Support System Group of Dr. Z. Hussain. In October 2006, I obtained a joint position as Research Associate at Stanford University in Prof. Z. X. Shen's group and Beamline Scientist at the ALS in the User Support System Group of Dr. Z. Hussain. I became an Assistant Professor in the Physics Department at UTK in August 2007. For a full CV, including full publications record, go here.
For Prospective Students and Post-Doctoral Fellows
Our group is composed of two postdoctoral researchers (Dr. Cheney and Dr. Vilmercati) and one undergraduate student (E. Martin). A couple of positions are immediately available for highly motivated graduate students who are interested in the study of novel materials and complex electron systems with soft x-ray spectroscopies. If interested, please e-mail (firstname.lastname@example.org) or call me in the office (4-6123). A description of our research activities and ongoing projects may be found here.
X-Ray Absorption Spectroscopy of Ba(Fe1-XCox)2As2 Superconductors: Electronic Structure, Orbital Symmetry and Bonding Topology
C. Parks Cheney, F. Bondino, T. A. Callcott, P. Vilmercati, D. Ederer, F. Parmigiani, W. L. Yang, A. S. Sefat, M. A. McGuire, R. Jin, B. C. Sales, D. Mandrus, D. J. Singh, J. W. Freeland, and N. Mannella
Phys. Rev. B 81, 104518 (2010)
Universal versus Material-Dependent Two-Gap Behaviors of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4
T. Yoshida, M. Hashimoto, S. Ideta, A. Fujimori, K. Tanaka, N. Mannella, Z. Hussain, Z.-X. Shen, M. Kubota, K. Ono, Seiki Komiya, Yoichi Ando, H. Eisaki, and S. Uchida
Physical Review Letters 103, 037004 (2009)
Evidence for three-dimensional Fermi-surface topology of the layered electron-doped iron superconductor Ba(Fe1-xCox)2As2
P. Vilmercati, A. Fedorov, I. Vobornik, U. Manju, G. Panaccione, A. Goldoni, A. S. Sefat, M. A. McGuire, B. C. Sales, R. Jin, D. Mandrus, D. J. Singh, and N. Mannella Physical Review B 79, 220503(R) (2009)
Energy gaps in the failed high-Tc superconductor La1.875Ba0.125CuO4
Rui-Hua He, Kiyohisa Tanaka, Sung-Kwan Mo, Takao Sasagawa, Masaki Fujita, Tadashi Adachi, Norman Mannella, Kazuyoshi Yamada, Yoji Koike, Zahid Hussain and Zhi-Xun Shen
Nature Physics 5, 119 (2009)
Evidence for Strong Itinerant Spin Fluctuations in the Normal State of CeFeAsO0.89F0.11 Iron-Oxypnictide Superconductors
F. Bondino, E. Magnano, M. Malvestuto, F. Parmigiani, M. A. McGuire, A. S. Sefat, B. C. Sales, R. Jin, D. Mandrus, E. W. Plummer, D. J. Singh, and N. Mannella Physical Review Letters 101, 267001 (2008)
Polaron coherence condensation as the mechanism for colossal magnetoresistance in layered manganites
N. Mannella, W. Yang, K. Tanaka, X. J. Zhou, H. Zheng, J. F. Mitchell, J. Zaanen, T. P. Devereaux, N. Nagaosa, Z. Hussain and Z.-X. Shen
Phys. Rev. B 76, 233102 (2007)
Monochromatic electron photoemission from diamondoid monolayers
W.L. Yang, J.D. Fabbri, T.M Willey, J.R.I. Lee, J.E. Dahl, R.M.K. Carlson, P. R. Schreiner, A. A. Fokin, B.A. Tkachenko, N.A. Fokina, W. Meevasana, N. Mannella, K. Tanaka, X.J. Zhou, T. van Buuren, M.A. Kelly, Z. Hussain, N.A. Melosh and Z.X. Shen
Science 316, 1460 (2007)
Nodal Quasiparticle in Pseudogapped Colossal Magnetoresistive Manganites
N. Mannella, W. Yang, X. J. Zhou, H. Zheng, J. F. Mitchell, J. Zaanen, T. P. Devereaux, N. Nagaosa, Z. Hussain and Z.-X. Shen
Nature 438, 474 (2005)
Direct Observation of High-Temperature Polaronic Behavior in Colossal Magnetoresistive Manganites
N. Mannella, A. Rosenhahn, C. H. Booth, S. Marchesini, B.S. Mun, S.-H. Yang, K. Ibrahim, Y. Tomioka and C.S. Fadley,
Physical Review Letters 92, 166401 (2004)
Highlights in the Press
A Class of Their Own - New Superconductors Defy Conventional Models
Highlighted in UT Physics News, July 13 (2009)
Polaron Coherence Condensation in Layered Colossal Resistive Manganites
Highlighted in ALSNews vol. 289, July 30 (2008)
Experiments debunk 'pseudogap' role in superconductivity, pave way to practical superconductors
Highlighted in Physorg.com/news10505, Feb. 2 (2006)
Experiments debunk 'pseudogap' role in superconductivity
Highlighted in Stanford Report, Feb. 1 (2006)
Pseudogaps Are Not The Answer
Highlighted in Science @ Berkeley Lab., Jan 30 (2006)
Pseudogaps, polarons, and the mystery of high-Tc superconductivity
Highlighted in ALSNews, vol. 264 (2006)
Condensed-matter physics: Focus on the Fermi surface
Highlighted in Nature 438, 435 (2005)
A Different Spin on Future Data Storage
Highlighted in Science @ Berkeley Lab., March 03 (2005)
Polaron Behavior in CMR Manganites
Highlighted in ALSNews, vol. 249 (2005)