Georg Ehlers

Georg Ehlers

Position: Lead Instrument Scientist

Instrument: Cold Neutron Chopper Spectrometer

Group: Time-of-Flight Spectroscopy

Division: Quantum Condensed Matter Division

Facility: Spallation Neutron Source

Contact: ehlersg@ornl.gov or (865) 206-0824

Dr. Ehlers joined the Spallation Neutron Source (SNS) in 2003 as the lead instrument scientist for beam line 5, the Cold Neutron Chopper Spectrometer (CNCS). CNCS is a high-resolution, direct geometry, cold neutron, inelastic multi-chopper spectrometer, designed to make use of neutrons with an energy of <50 meV.

Before joining the SNS, Dr. Ehlers worked at the Institute Laue-Langevin (ILL), a leading European neutron research facility situated in Grenoble, France for six years. At the ILL, he was an instrument scientist for the spin-echo spectrometers IN11 and IN15, and established a strong research program using the neutron spin echo technique in the study of geometrically frustrated and other exotic magnetic materials. While at the ILL, he also helped launch a project to build a new spin echo instrument known as the Wide Angle Neutron Spin Echo Spectrometer Project (WASP).

Dr. Ehlers has published more than 140 research articles in international peer reviewed journals. He is a referee for the APS journals, the Journal of Physics Condensed Matter, Physical Chemistry Chemical Physics, and Nuclear Instruments and Methods.

Education

PhD in Experimental Condensed Matter Physics, the Hahn Meitner Institut, in Berlin, Germany

Selected Publications

C. W. Li, J. Hong, A. F. May, D. Bansal, S. Chi, T. Hong, G. Ehlers, and O. Delaire, “Orbitally driven giant phonon anharmonicity in SnSe”, Nature Physics 11 1063 (2015)

G. Ehlers, J. R. Stewart, P. P. Deen, and K. H. Andersen, “Neutron xyz–polarization analysis at a time-of-flight instrument”, EPJ Web of Conferences 83 03004 (2015)

P. Das, S.-Z. Lin, N. J. Ghimire, K. Huang, F. Ronning, E. D. Bauer, J. D. Thompson, C. D. Batista, G. Ehlers, and M. Janoschek, “Magnitude of the Magnetic Exchange Interaction in the Heavy-Fermion Antiferromagnet CeRhIn5”, Physical Review Letters 113 246403 (2014)

L. Clark, G.  J. Nilsen, E. Kermarrec, G. Ehlers, K.  S. Knight, A. Harrison, J.  P Attfield, and B.  D. Gaulin, “From Spin Glass to Quantum Spin Liquid Ground States in Molybdate Pyrochlores”, Physical Review Letters 113 117201 (2014)

C. W. Li, O. Hellman, J. Ma, A. F. May, H. B. Cao, X. Chen, A. D. Christianson, G. Ehlers, D. J. Singh, B. C. Sales, and O. Delaire, “Phonon self-energy and origin of anomalous neutron scattering spectra in SnTe and PbTe thermoelectrics”, Physical Review Letters 112 175501 (2014)

M. B. Stone, J. L. Niedziela, D. L. Abernathy, L. DeBeer-Schmitt, G. Ehlers, O. Garlea, G. E. Granroth, M. Graves-Brook, A. I. Kolesnikov, A. Podlesnyak, and B. Winn, “A comparison of four direct geometry time-of-flight spectrometers at the Spallation Neutron Source”, Review of Scientific Instruments 85 045113 (2014)

H. J. Silverstein, K. Fritsch, F. Flicker, A. M. Hallas, J. S. Gardner, Y. Qiu, G. Ehlers, A. T. Savici, Z. Yamani, K. A. Ross, B. D. Gaulin, M. J. P. Gingras, J. A. M. Paddison, K. Foyevtsova, R. Valenti, F. Hawthorne, C. R. Wiebe, and H. D. Zhou, “Liquidlike correlations in single-crystalline Y2Mo2O7: An unconventional spin glass”, Physical Review B 89 054433 (2014)

G. Ehlers, A. A. Podlesnyak, S. E. Hahn, R. S. Fishman, O. Zaharko, M. Frontzek, M. Kenzelmann, A. V. Pushkarev, S. V. Shiryaev, and S. Barilo, “Incommensurability and spin dynamics in the low-temperature phases of Ni3V2O8”, Physical Review B 87 214418 (2013)

J. Ma, O. Delaire, A. F. May, C. E. Carlton, M. A. McGuire, L. H. VanBebber, D. L. Abernathy, G. Ehlers, Tao Hong, A. Huq, Wei Tian, V. M. Keppens, Y. Shao-Horn, and B. C. Sales, “Glass-like phonon scattering from a spontaneous nanostructure in AgSbTe2”, Nature nanotechnology 8 445-451 (2013)

J. Lee, M. B. Stone, A. Huq, T. Yildirim, G. Ehlers, Y. Mizuguchi, O. Miura, Y. Takano, K. Deguchi, S. Demura, and S.-H. Lee, “Crystal structure, lattice vibrations, and superconductivity of LaO(1−x)F(x)BiS2”, Physical Review B 87 205134 (2013)

S. Perticaroli, J. D. Nickels, G. Ehlers, H. O'Neill, Q. Zhang, and A. P. Sokolov, “Secondary structure and rigidity in model proteins”, Soft Matter 9 9548-9556 (2013)

J. D. Nickels, H. O’Neill, L. Hong, M. Tyagi, G. Ehlers, K. L. Weiss, Q. Zhang, Z. Yi, E. Mamontov, J. C. Smith, and A. P. Sokolov, “Dynamics of protein and its hydration water: neutron scattering studies on fully deuterated GFP”, Biophysical Journal 103 1566-1575 (2012)

F. Ye, R. S. Fishman, J. A. Fernandez-Baca, A. A. Podlesnyak, G. Ehlers, H. A. Mook, Y. Wang, B. Lorenz, and C. W. Chu, “Long-range magnetic interactions in the multiferroic antiferromagnet MnWO4”, Physical Review B 83 140401 (2012)

O. Delaire, J. Ma, K. Marty, A. F. May, M. A. McGuire, M. H. Du, D. J. Singh, A. Podlesnyak, G. Ehlers, M. D. Lumsden, and B. C. Sales, “Giant anharmonic phonon scattering in PbTe”, Nature materials 10 614-619 (2011)

G. Ehlers, A. A. Podlesnyak, J. L. Niedziela, E. B. Iverson, and P. E. Sokol, “The new cold neutron chopper spectrometer at the Spallation Neutron Source: design and performance”, Review of Scientific Instruments 82 085108 (2011)

M. Frontzek J. T. Haraldsen, A. Podlesnyak, M. Matsuda, A. D. Christianson, R. S. Fishman, A. S. Sefat, Y. Qiu, J. R. D. Copley, S. Barilo, S. V. Shiryaev, and G. Ehlers, “Magnetic excitations in the geometric frustrated multiferroic CuCrO2”, Physical Review B 84 094448 (2011)