Dr. Jiufeng J. Tu
J-330A, Physics Dept.
390 Ft. Washington Avenue
160 Convent Avenue
APT. 10A
The City College of New York
New York, NY 10033
New York, NY 10031
Tel: (646)-894-5264 (Cell)
Tel: (212)-650-5558 (Office)
E-mail: jtu@bnl.gov
(212)-650-6913 (Lab)
E-mail: (U.S. Citizen)
E-mail: jtu@sci.ccny.cuny.edu
http://mail.sci.ccny.cuny.edu/~jtu/
___________________________________________________________________________________
CURRENT RESEARCH:
My laboratory employs optical spectroscopic techniques to study low dimensional electronic systems
and nano-systems. The main experimental tools used are Fourier transform infrared spectroscopy and
Raman spectroscopy. Efforts are underway to couple these spectroscopic methods with strong magnetic
fields and the intense THz synchrotron radiation. Currently, there are two major areas of research:
(i) Optical studies of superconductors and 2D-layered cobaltates: including high temperature
superconductors and the newly discovered superconductor MgB2. Infrared spectroscopy is ideal for
the study of charge dynamics and gap properties in superconductors. Coupled with strong magnetic
fields and synchrotron radiation, we are developing infrared spectroscopy into one of the major
tools that would shine the light on the paring mechanisms in various kinds of superconductors.
(ii) Optical studies of nano-systems: these include ultra-thin films, nano-wires and nano-magnets like
the single molecule magnets (SMMs). Optical spectroscopy, particularly in the THz region,
provides a unique “contactless” probe to study these low-dimensional nano-systems, when
traditional transport measurements are difficult or sometimes impossible to be performed.
CURRENT GRANTS:
1. Sarachik, M.P. and Tu, J.J., “Spectroscopic and Local Magnetic Measurements in High-Spin
Molecular Magnets”, NSF, $480,000 from 01/15/2005 – 01/15/2009.
2. Tu, J.J., Sarachik, M.P, and Birman, J.L., “Spectroscopic Investigation of Magnetic Quantum
Tunneling in Mn12 acetate and the mm-Wave Radiation at Avalanches”, PSC-CUNY Equipment
Grant, $49,753 from 06/01/2004-06/01/2006.
3. Tu, J.J., “Infrared Studies of Anisotrpic El-Ph Interactions in MgB2”, PSC-CUNY 35-36, $3,021
from 06/01/2005-12/30/2006.
4. Tu, J.J., “Polarized Infrared Studies of Optimally-doped Bi2212”, PSC-CUNY 34-35, $5,022 from
06/01/2004-12/30/2005.
EDUCATION and PROFESSIONAL EXPERIENCE:
International Baccalaureate
A.B. & A.M.
M.S.
Ph.D.
Research Associate
Visiting Assistant Prof.
Assistant Prof. of Physics
United World College of the Atlantic, Wales, UK, June 1989.
Harvard University, Physics, June 1993.
Cornell University, Physics, August 1996.
Cornell University, Physics, January 2000.
Brookhaven National Laboratory, February 2000- January 2003
University of North Carolina at Charlotte, January 2003- May 2003
The City College of New York, September 1, 2003- present
ACADEMIC DISTINCTIONS:
Young Scientist Award, the Royal Swedish Youth Association, 1988, for which I had the honor to
attend the Nobel Prize ceremony in Stockholm that year.
John Harvard Scholarship for academic achievement of the highest distinction, 1989-1990.
Harvard College Scholarship for academic achievement with distinction, 1990-93.
A.B. in Physics, Magna Cum Laude, Harvard University, June 1993.
Member of the American Physical Society and Referee for Physical Review journals
Proposal Review Panel Member (National Synchrotron Light Source at Brookhaven National Lab.)
RESEARCH EXPERIENCE:
Post-doctorial Research with Dr. M. Strongin (Physics Department, Brookhaven National Laboratory,
February 2000 to January 2003):
● Participated in a LDRD (Laboratory Directed Research Development) program to study charge
transfer mechanisms in nano-systems.
● Studied the charge dynamics in low dimensioanl electron systems using infrared spectroscopy;
samples include high temperature superconductors (Bi2212, LSCO), the new superconductor MgB2
and other 2D-layered electron systems (cobaltates).
● Examined the properties of ultra-thin metal films (Pb, Au) using both transport techniques and far
infrared spectroscopy; explored ways to study the optical properties of low dimensional nano-systems
using ultra-thin metal films as the templates.
Graduate Research with Professor A. J. Sievers (Laboratory of Atomic and Solid State Physics,
Cornell University, Sept., 1993-Jan., 2000):
● Studied the low frequency and low temperature glass-like properties of fluorite mixed crystal, alkali
halide mixed crystals and some glasses using Raman spectroscopy. First observation of Raman
scattering by two level systems (TLS) in disordered solids. As a result the low frequency Raman
scattering technique has become a valuable tool for the study of TLS.
● Maintained and developed the Dilor XY Raman setup as part of Cornell University’s optical user
facility with duties including designing of many optical components, writing proposals to build up
capabilities and trouble shooting.
● Examined the properties of isolated impurities in otherwise perfect crystals using Raman
spectroscopy; samples include KI+Ag+, KI+Br-, KBr+SH- and KCl+Se2-.
● Studied far infrared and Raman properties of quasi-crystal AlMnPd.
● Examined the lattice phonon properties of perfectly ordered crystals using Raman spectroscopy in
CuCl, GaP, ZnS and ZnSe to search for evidence of vibrational localization due to anharmonicity.
● Mastered different types of spectroscopic techniques including far- and mid- infrared FT
spectroscopy, conventional Raman spectroscopy, resonant Raman spectroscopy, optical emission
spectroscopy and optical absorption spectroscopy. Acquired knowledge on the design and
maintenance of different types of spectrometers and obtained extensive machine shop skills.
Undergraduate Research with Professor M. Tinkham (Physics Dept, Harvard University, 1992-1993):
● Studied microwave effects on arrays of superconducting Josephson junctions.
● Exposed to many different aspects of conventional BCS superconductivity.
● Learned sub-Kelvin cryogenic techniques.
SELECTED JOURNAL PUBLICATIONS:
1. “An Inhomogeneous Josephson Phase Near the (Super) Conductor-Insulator Transition”, J. J. Tu,
M. Strongin and Y. Imry, arXiv:cond-mat/0405625, Phys. Rev. B, submitted (2005).
2. “Transient Infrared Photo-reflectance Study of Superconducting MgB2: Evidence for Multiple Gaps
and Interband Scattering”, R. P. S. M. Lobo, J. J. Tu, Eun-Mi Choi, Hyeong-Jin Kim, W. N.
Kang, Sung-Ik Lee, and G. L. Carr, arXiv:cond-mat/0404708, Phys. Rev. Lett., submitted (2005).
3. “The Absence of Superfluid Response in ac and bc-plane Optical Conductivities of Optimallydoped Bi2212 Single Crystals in the Surface Region”, J. J. Tu, C. C. Homes, L. H. Greene, G. D.
Gu, and M. Strongin, arXiv:cond-mat/0307582, Phys. Rev. Lett., submitted (2005).
4. “Extracting the electron-boson spectral function alpha2F (omega) from infrared and photoemission
data using inverse theory”, S.V. Dordevic, C.C. Homes, J. J. Tu, T. Valla, M. Strongin, P.D.
Johnson, G.D. Gu, D.N. Basov, Phys. Rev. B 71, 104529 (2005).
5. “Marginal Fermi liquid analysis of 300 K reflectance of doped Bi2Sr2CaCu2O8+”, J. Hwang, T.
Timusk, A. V. Puchkov, N. L. Wang, G. D. Gu, C. C. Homes, J. J. Tu, H. Eisaki, Phys. Rev. B 69,
094520 (2004).
6. “Magneto-Optical Studies of the Critical States in c-axis Oriented MgB2 Thin Film and Bulk
MgB2/Mg Nano-Composites”, Z. Ye, Q. Li, G. D. Gu, J. J. Tu, W. N. Kang, Eun-Mi Choi,
Hyeong-Jim Kim, and Sung-Ik Lee, IEEE Tran. Applied Supercond. 13, 3722-3725 (2003).
7. “Angle-resolved Photoemission Spectroscopy and Optical Renormalizations: Phonons or Spin
Fluctuations”, E. Schachinger, J. J. Tu, J. P. Carbotte, Phys. Rev. B 67, 214508 (2003).
8. “On the Optical Activity of the Boson Peak and Two-level Systems in Silica-germania Glasses”,
B.E. Hubbard, J. J. Tu, N.I. Agladze and A.J. Sievers, Phys. Rev. B 67, 144201 (2003).
9. “Optical Properties of Ultra-thin Films: Evidence for a Dielectric Anomaly at the Insulator to
Metal Transition”, J. J. Tu, C. C. Homes and M. Strongin, Phys. Rev. Lett. 90, 017402 (2003).
10. “The Mid-infrared Hall Effect in Optimally-doped Bi2Sr2CaCu2O8+”, D.C. Schmadel, J. J. Tu, L.
B. Rigal, D. B. Romero, M. Grayson, G.D. Gu and H. D. Drew, arXiv:cond-mat/0210304,
submitted to Phys. Rev. Lett. (2002).
11. “Optical Studies of Charge Dynamics in the Optimally Doped Bi2Sr2CaCu2O8+ Single Crystals”,
J. J. Tu, C. C. Homes, G. D. Gu, D. N. Basov and M. Strongin, Phys. Rev. B 66, 144514 (2002).
12. “Experimental Study of Raman-active Two-level Systems in LaF3 doped Fluorite Mixed Crystals”,
J. J. Tu and A. J. Sievers, Phys. Rev. B 66, 094206 (2002).
13. “Experimental Study of Raman-active Two-level Systems in Soda-lime-silica and Lead Oxide
Glasses”, J. J. Tu and A. J. Sievers, Phys. Rev. B 65, 144204 (2002).
14. “A Systematic Opitcal Study of Phonon Properties in Optimally Doped Bi2Sr2CaCu2O8+ Single
Crystals”, J. J. Tu, C. C. Homes, G. D. Gu and M. Strongin, Physica B 316-317, 324 (2002).
15. “Low-frequency Raman Study of Glass-like Properties of Mixed Crystals with the Fluorite
Structure”, J. J. Tu and A.J. Sievers, Physica B 316-317, 316 (2002).
16. “Infrared and Raman Study of Two-level Systems in Fiber Optic Quality a-SiO2 and a-SiO2:GeO2”,
B.E. Hubbard, N.I. Agladze, J. J. Tu and A.J. Sievers, Physica B 316-317, 531 (2002).
17. “Optical Properties of c-axis Oriented Superconducting MgB2 Films”, J. J. Tu, G. L. Carr, V.
Perebeinos, C. C. Homes, M. Strongin, P. B. Allen, W. N. Kang, Eun-Mi Choi, Hyeong-Jin Kim,
and Sung-Ik Lee, Phys. Rev. Lett. 87, 277001 (2001).
18. “High Resolution x-ray Emmission and Adsorption Study of the Valence Band Electronic Structure
of MgB2”, C. McGuinness, K. E. Smith, S. M. Butorin, J.H. Guo, J. Nordgren, T. Vogt, G.
Schneider, J. Reilly, J.J. Tu, P. D. Johnson, and D. K. Shuk, Europhys. Lett. 56, 112 (2001).
19. “Total Number Density of Raman-Active Two Level Systems in Fluorite Mixed Crystals and the
Law of Mass Action”, J. J. Tu and A. J. Sievers, Phys. Rev. Lett. 83, 4077 (1999).
20. “Mm-Wave Absorption and Raman Scattering From Glass-like Features in Fluorite Mixed
Crystals”, A. J. Sievers, J. J. Tu, N. Agladze, S. A. Fitzgerald, J. A. Campbell, Physica B 244, 159
(1998).
21. “Raman Scattering From Glass-like Features in Mixed Fluorite Crystals”, J. J. Tu, J. A.
Campbell, and A. J. Sievers, Mater. Sci. Forum 239-242, 485 (1997).
22. “Glass-like Properties Observed in Low-Frequency Raman Scattering of Mixed Fluorite Crystals”,
J. J. Tu, S. A. Fitzgerald, J. A. Campbell and A. J. Sievers, J. NonCryst. Solids 202, 153 (1996).
SELECTED INVITED TALKS:
● “Shining the Light on MgB2: Two Superconductors in One?”, J. J. Tu, Condensed Matter Seminar,
May 18, 2005, Physics Department, City College of New York, New York City, NY.
● “Magnetic Field Dependent Far-infrared Studies of Epitaxial MgB2 Films”, J. J. Tu, Condensed
Matter Seminar, February 23, 2005, Brookhaven National Laboratory, Upton, NY.
● “Shining the Light on Ultra-thin Films”, J. J. Tu, International Thin Films Workshop II , January 67, 2005, Brookhaven National Laboratory, Upton, NY.
● “Infrared Exploration of Electrons in Superconductors”, J. J. Tu, Condensed Matter Seminar, June
20, 2004, Physics Department, University of Maryland, College Park, MD.
● “Infrared Exploration of Electrons in Superconductors”, J. J. Tu, Condensed Matter Seminar,
November 13, 2003, Physics Department, University of Connectict, Storrs, Connectict.
● “Probing Superconductors with Infrared: Experimental Studies of Electron-boson Interactions”, J.
J. Tu, Condensed Matter Seminar, November 14, 2002, Physics Department, Brookhaven National
Laboratory, Upton, New York.
● “Infrared Studies of Electron-boson Interactions in Superconductors”, J. J. Tu, International
Conference on the Low Energy Electrodynamics in Solids (LEES’02), October 13-18, 2002,
Montauk, New York.
● “Probing Superconductors with Infrared”, J. J. Tu, Condensed Matter Seminar, April 4, 2002,
Physics Department, University of Viginia, Charlottesville, Virginia.
● “Optical Studies of Charge Dynamics in Ultra-thin Metal Films, Thick MgB2 Films and HTSC: is
There a Common Theme?”, J. J. Tu, International Workshop on Networks and Nanoscale
Coherence in 2D Metals and HTSC, sponsored by the Theoretical Physics Institute, University of
Alberta, August 20-25, 2001, Banff, Canada.
● “Optical Properties of c-axis Orientated Superconducting MgB2 Films”, J. J. Tu, CondensedMatter Lunch Seminar, July 9, 2001, Brookhaven National Laboratory, Upton, New York.
● “Experimental Evidence of Spin-Charge Coupling in Bi2212”, J. J. Tu, NSLS Seminar, June 8,
2001, Brookhaven National Laboratory, Upton, New York.
● “Experimental Evidence of Spin-Charge Coupling in the Optical Studies of Bi2212 and Cobaltates”,
J. J. Tu, Condensed Matter Lunch Seminar, January 29, 2001, Brookhaven National Laboratory,
Upton, New York.
● “Total Number Density of Raman-Active Two Level Systems in Fluorite Mixed Crystals and the Law
of Mass Action”, J. J. Tu, the Laboratory of Atomic and Solid State Physics Seminar, July 19,
1999, Cornell University, Ithaca, New York.
SELECTED CONTRIBUTED TALKS:
● “Magnetic Field and Carbon-doping Dependent Far-infrared Studies of Epitaxial MgB2 Films”, J.
J. Tu et al., 2005 March Meeting of the American Physical Society, Los Angeles, CA., U.S.A.
● “Magnetic Field Dependent Far-infrared Studies of Manganese-based Single-molecule Magnets”,
J. J. Tu et al., 2005 March Meeting of the American Physical Society, Los Angeles, CA., U.S.A.
● “A Systematic Infared Studies of Phonon Properties in Optimally-doped Bi2Sr2CaCu2O8+ Single
Crystals”, J. J. Tu et al., 2004 March Meeting of the American Physical Society, Montreal.
● “Optical Studies of Electron-boson Interactions in Nb and Bi2Sr2CaCu2O8+ Single Crystals”, J. J.
Tu et al., 2003 March Meeting of the American Physical Society, Austin.
● “Optical Properties of c-axis Oriented Superconducting MgB2 Films”, J. J. Tu et al., 2002 March
Meeting of the American Physical Society, Indianapolis.
● “A Systematic Opitcal Study of Phonon Properties in Optimally Doped Bi2212”, and “Lowfrequency Raman Study of Glass-like Properties of Mixed Crystals with the Fluorite Structure,”, J.
J. Tu et al., 2001, Phonons 2001, Hanover.
● “The Absence of Superfluid Response in the Optical Conductivity of the Edge Region of Optimally
Doped Bi2212”, J. J. Tu et al., 2001 March Meeting of the American Physical Society, Seattle.
● “Optical Conductivity as a Probe of the Nature of Ultra Thin Layers”, J. J. Tu et al., 2001 March
Meeting of the American Physical Society, Seattle.
● “Low-Frequency Raman Study of Glass-like Properties of Mixed Crystals with the Fluorite
Structure”, J .J. Tu et al., 1999 March Meeting of the American Physical Society, Atlanta.
● “Raman Scattering and Far Infrared Absorption From Glass-like Features in Fluorite Mixed
Crystals”, J. J. Tu, S. A. FitzGerald, J. A. Campbell, and A. J. Sievers, 1998 Disorder in Materials
Gordon Research Conference, New London.
● “Raman Scattering From Glass-like Features in Mixed Fluorite Crystals”, J. J. Tu, J. A.
Campbell, and A. J. Sievers, 1996 International Conference on Defects in Insulating
Materials,Winston-Salem.
● “Glass-like Properties Observed in Low-Frequency Raman Scattering of Mixed Fluorite Crystals”,
J. J. Tu et al., 1996 March Meeting of the American Physical Society, St. Louis.
● “Raman Scattering From Two Level Systems in Fluorite Mixed Crystals”, J. J. Tu, J. A. Campbell,
S. A. FitzGerald and A. J. Sievers, 1995 The 13th University Conference on Glass Science, Troy.