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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

 

Tel: (631) 344-7579

Fax: (631) 344-2739

email: homes@bnl.gov

C. C. Homes

 

Curriculum vitae

 

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).

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Education, professional experience

Honours and awards

  • NSERCC Postdoctoral Fellowship ('92)

  • Brookhaven Science and Technology Award ('07)

  • Fellow, American Physical Society ('08)

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Research Interests & Experimental Program

 

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 on electronic phenomena in strongly correlated electron systems.  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 studied.  Of particular interest strongly correlated electron systems with particular attention on the high-temperature superconductors:

  • Pseudogap in the cuprate superconductors

  • Charge- and spin-stripe order in transition metal oxides

  • The new iron-based superconductors

  • Topological insulators and their response under high pressure

Most 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; in the case of Ba0.6K0.4Fe2As2 this has revealed an unusual non-Fermi liquid response in the electron pocket. 

 

 

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Recent Publications (full publication list)

  • Fate of quasiparticles in the superconducting state, S. V. Dordevic, D. van der Marel, and C. C. Homes, Phys. Rev. B 90, 174508 (2014). PDF

  • Optical conductivity of nodal metals, C. C. Homes, J. J. Tu, J. Li, G. D. Gu and A. Akrap, Sci. Rep. 3, 3446 (2013). PDF

  • 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). PDF

  • Doping for superior dielectrics, C. C. Homes and T. Vogt, Nat. Mater. 12, 782 (2013). PDF

  • 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). PDF

  • ns-Tc correlations in granular superconductors, Y. Imry, M. Strongin and C. C. Homes, Phys. Rev. Lett. 109, 067003 (2012). PDF

  • 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). PDF

  • 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). PDF

  • 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). PDF

Book Chapters

  • 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). PDF

  • 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). PDF

  • Scaling laws in high-temperature superconductors as revealed through infrared spectroscopy, C. C. Homes, Synchrotron Radiation News 18, 9-14 (2005). PDF

  • 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). PDF

  • 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). PDF

  • 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). PDF

  • Synchrotron infrared photoacoustic spectroscopy, Kirk. H. Michaelian, Richard S. Jackson, and Christopher C. Homes, Rev. Sci. Inst. 72, 4331-4336 (2001). PDF

  • 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). PDF The original paper contains an error in Fig. 2; the corrected figure is shown in  erratum in Physica C 432, 316 (2005). PDF

  • 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). PDF (zipped postscript)

  • 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). PDF

  • 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). PDF

  • 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). PDF

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Useful links

 

BNL and NSLS Infrared links:

Physics related links:

Optics and superconductivity links:

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Personal Musings (a joke, as told by Bob Dynes)

 

A man in a hot air balloon realized he was lost.  He reduced altitude and spotted a woman below. He descended a bit more and shouted, "Excuse me, can you help me? I promised a friend I would meet him an hour ago, but I don't know where I am."

The woman below replied, "You're in a hot air balloon hovering approximately 30 feet above the ground. You're between 40 and 41 degrees north latitude and between 59 and 60 degrees west longitude."

"You must be an physicist," said the balloonist. "I am," replied the woman, "How did you know?"

"Well," answered the balloonist, "everything you told me is, technically correct, but I've no idea what to make of your information, and the fact is I'm still lost. Frankly, you've not been much help at all. If anything, you've delayed my trip."

The woman below responded, "You must be in Management." "I am," replied the balloonist, "but how did you know?"

"Well," said the woman, "you don't know where you are or where you're going. You have risen to where you are due to a large quantity of hot air. You made a promise which you've no idea how to keep, and you expect people beneath you to solve your problems. The fact is you are in exactly the same position you were in before we met, but now, somehow, it's my fault."

 

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Last modified: Monday, November 28, 2016 03:03 PM.