Christopher C. Homes
Physicist, Electron Spectroscopy Group
Infrared and Terahertz Spectroscopy
Fellow, American Physical Society
Condensed Matter Physics & Materials Science
Dept. - Bldg. 734
Brookhaven National Laboratory
734 Brookhaven Avenue
P.O. Box 5000
Upton, NY 11973-5000
Welcome to my personal home page! I am a
physicist in the Electron Spectroscopy Group in the
Condensed Matter Physics and Materials Science Department at
Brookhaven National Laboratory,
where I study the interaction of light with solids, and pretty much
anything else too slow to get out of the way. If you would like to learn more about the fundamentals of
infrared spectroscopy, you can view a PDF file of a monograph
Fourier-transform infrared spectroscopy
(recently revised) that I am working on, but have not yet finished
(you will need Adobe Acrobat Reader to view this document). By the
way, the picture on the screen is a part of the Fermi surface of the
perfectly-compensated semimetal WTe2, a colossal magnetoresistance
summa cum laude,
McMaster University ('83)
University of British Columbia ('85,'90)
Postdoc., McMaster ('90-'92)
NSERCC Postdoc. & Research Assoc.,
Simon Fraser University ('92-'96)
Physicist, BNL ('01-present,
granted tenure in '03)
Visiting Professor (Paris VI),
Laboratoire Photons et Matière, ESPCI ('07)
Honours and awards
NSERCC Postdoctoral Fellowship ('92)
Brookhaven Science and Technology Award ('07)
Fellow, American Physical Society ('08)
I am primarily interested in using infrared radiation
to probe the electronic and vibrational properties of solids. The
reflectance of a material is a complex quantity, with an amplitude
and a phase. During a typical experiment, we only measure the
reflected amplitude of the radiation. However, if the reflectance is
measured over a wide enough range, then it is possible using the
Kramers-Kronig relation to calculate the phase: once the amplitude
and phase are known, then other optical response functions may be
calculated, specifically the real part of the complex conductivity.
The current focus of my research is strongly correlated electron systems,
with special attention on systems that show emergent behavior, such
as the cuprate, and more recently the iron-based, superconductors.
I am also interested in the Dirac and Weyl semimetals; recent work
has also included
the colossal thermopower material FeSb2. We have extended our
infrared techniques well into the terahertz region (1 THz = 33.3 cm-1),
allowing the low-energy collective modes of these systems to be
Pseudogap in the underdoped cuprate superconductors
and spin-stripe order in transition metal oxides
Dirac and Weyl semimetals
Colossal magentoresistance and thermopower materials
First principle methods for determining electronic strucure and
Much of our current work is on the
iron-based superconductors. ARPES and density functional
theory both indicate that the iron-based materials are multiband
systems with electron and hole pockets; we therefore approach the
conductivity using the so-called "two-Drude" model to extract the
temperature dependence of the two different types of carriers;
allowing hidden non-Fermi liquid behavior to be studied.
I am also involved with the validation component in the Center for
Computational Material Spectroscopy and Design (Comscope).
Fate of quasiparticles in the superconducting state,
S. V. Dordevic, D. van der Marel, and C. C. Homes,
Phys. Rev. B 90, 174508 (2014).
Optical conductivity of nodal metals,
C. C. Homes, J. J. Tu, J. Li, G. D. Gu and A. Akrap,
Sci. Rep. 3, 3446 (2013).
Hidden T-linear scattering rate in Ba0.6K0.4Fe2As2,
Y. M. Dai, B. Xu, B. Shen, H. Xiao, H. H. Wen, X. G. Qiu, C. C. Homes, and R. P. S. M. Lobo,
Phys. Rev. Lett. 111, 117001 (2013).
Doping for superior dielectrics,
C. C. Homes and T. Vogt, Nature Mater. 12, 782 (2013).
Do organics and other exotic superconductors fail universal scaling relations?
S. V. Dordevic, D. N. Basov, and C. C. Homes,
Sci. Rep. 3, 1713 (2013).
ns-Tc correlations in granular superconductors,
Y. Imry, M. Strongin and C. C. Homes,
Phys. Rev. Lett. 109, 067003 (2012).
Determination of the optical properties of La2-xBaxCuO4 for several
dopings, including the anomalous x=1/8 phase,
C. C. Homes, M. Hücker, Q. Li, Z. J. Xu, J. S. Wen, G. D. Gu, and J. M. Tranquada,
Phys. Rev. B 85, 134510 (2012).
Electronic correlations and unusual superconducting response in the optical properties of
the iron chalcogenide FeTe0.55Se0.45,
C. C. Homes, A. Akrap, J. S. Wen, Z. J. Zu, Z. W. Lin, Q. Li, and G. D. Gu,
Phys. Rev. B 81, 180508(R) (2010).
Infrared phonon anomaly in BaFe2As2,
A. Akrap, J. J. Tu, L. J. Li, G. H. Cao, Z. A. Xu, and C. C. Homes,
Phys. Rev. B 80, 180502(R) (2009).
Instrumentation for far-infrared spectroscopy,
P. R. Griffiths and C. C. Homes, Handbook of Vibrational Spectroscopy, Volume 1 - Theory and Instrumentation (Wiley, New York, 2001).
The infrared conductivities of semiconducting (TMTSF)2ReO4 and (TMTSF)2BF4,
compared with several model calculations,
C. C. Homes and J. E. Eldridge,
Organic Superconductivity, edited by V. Z. Kresin and W. A. Little (Plenum Press, New York, 1990), pp. 89-98.
Other notable works...
Silicon beam splitter for far-infrared and terahertz spectroscopy,
C. C. Homes, G. L. Carr, R. P. S. M. Lobo, J. D. LaVeigne, and D. B. Tanner,
Appl. Opt. 46, 7884 (2007).
Scaling laws in high-temperature superconductors as revealed through infrared spectroscopy,
C. C. Homes,
Synchrotron Radiation News 18, 9-14 (2005).
A universal scaling relation in high-temperature superconductors,
C. C. Homes, S. V. Dordevic, M. Strongin, D. A. Bonn, Ruixing Liang, W. N. Hardy, Seiki Komiya, Yoichi Ando,
G. Yu, N. Kaneko, X. Zhao, M. Greven, D. N. Basov and T. Timusk,
Nature 430, 539-541 (2004).
Phonon screening in high-temperature superconductors,
C. C. Homes, A. W. McConnell, B. P. Clayman, D. A. Bonn, Ruixing Liang, W. N. Hardy, M. Inoue,
H. Negishi, P. Fournier, and R. L. Greene,
Phys. Rev. Lett. 84, 5391-5394 (2000).
Optical response of high-dielectric-constant perovskite-related oxide,
C. C. Homes, T. Vogt, S. M. Shapiro, S. Wakimoto, and A. P. Ramirez,
Science 293, 673-676 (2001).
Synchrotron infrared photoacoustic spectroscopy,
Kirk. H. Michaelian, Richard S. Jackson, and Christopher C. Homes,
Rev. Sci. Inst. 72, 4331-4336 (2001).
Optical properties along the c-axis of YBa2Cu3O6+x,
for x=0.5 to 0.95: evolution of the pseudogap,
C. C. Homes, T. Timusk, Ruixing Liang, D. A. Bonn, and W. N. Hardy,
Physica C 254, 265-280 (1995).
The original paper contains an error in Fig. 2; the corrected figure is shown in erratum in
Physica C 432, 316 (2005).
Optical phonons polarized along the c-axis of YBa2Cu3O6+x, for x=0.5 to 0.95,
C. C. Homes, T. Timusk, D. A. Bonn, Ruixing Liang, and W. N. Hardy,
Can. J. Phys. 73, 663-675 (1995).
Optical properties along the c-axis of YBa2Cu3O6.70: evidence for a pseudogap,
C. C. Homes, T. Timusk, Ruixing Liang, D. A. Bonn, and W. N. Hardy,
Phys. Rev. Lett. 71, 1645-1648 (1993).
Technique for measuring the reflectance of irregular, submillimeter-sized samples,
C. C. Homes, M. Reedyk, D. A. Crandles, and T. Timusk,
Appl. Optics 32, 2976-2983 (1993).
The optical conductivity of the stable icosahedral quasicrystal Al63.5Cu24.5Fe12,
C. C. Homes, X. Wu, T. Timusk, Z. Altounian, A. Sahnoune, and J. O. Strom-Olsen,
Phys. Rev. Lett. 67, 2694-2696 (1991).
BNL and NSLS Infrared links:
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Optics and superconductivity links:
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Thursday, December 27, 2018 12:37 PM.