Girsh Blumberg

On the origin of critical nematic fluctuations in pnictide superconductors

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Authors:  S.-F. Wu, W.-L. Zhang, L. Li, H. B. Cao, H.-H. Kung, A. S. Sefat, H. Ding, P. Richard, and G. Blumberg Abstract:  We employ polarization-resolved Raman spectroscopy to study critical nematic fluctuations in Ba(Fe1-xAux)2As2 superconductors above and across well separated tetragonal to orthorhombic phase transition at temperature TS(x) and the Neel transition at TN(x). The static …

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Anomalous magneto-elastic coupling in Au-doped BaFe2As2

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Authors:  S.-F. Wu, W.-L. Zhang, L. Li, H.-B. Cao, H.-H. Kung, A. S. Sefat, H. Ding, P. Richard, and G. Blumberg Abstract:  We used polarization-resolved Raman scattering to study magneto-elastic coupling in Ba(Fe1-xAux)2As2 crystals as a function of light Au-doping, materials for which temperatures of the structural transition (TS) and of the magnetic ordering transition (TN) …

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Stripe quadrupole order in the nematic phase of FeSe1−xSx

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Authors:  W.-L. Zhang, S.-F. Wu, S. Kasahara, T. Shibauchi, Y. Matsuda, and G. Blumberg Abstract:  We use polarization-resolved electronic Raman spectroscopy to study charge dynamics in non-magnetic FeSe1-xSx superconductor. We observe two features of the XY quadrupole symmetry: a low-energy quasi-elastic peak (QEP) and an electronic continuum extending to high energy. The QEP exhibits critical enhancement …

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New paper published – Chiral Spin Mode on the Surface of a Topological Insulator

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Authors: H.-H. Kung, S. Maiti, X. Wang, S.-W. Cheong, D.L. Maslov, G. Blumberg Abstract: Using polarization-resolved resonant Raman spectroscopy, we explore collective spin excitations of the chiral surface states in a three dimensional topological insulator, Bi2Se3. We observe a sharp peak at 150 meV in the pseudovector A2 symmetry channel of the Raman spectra. By …

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Congradulations to Mai Ye and Other Group Members for their Departmental Awards

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We are proud to announce that graduate student Mai Ye has been awarded the David C. Langreth Graduate Development Award. This awarded is awarded to “promising early-stage graduate student, typically in the second year of graduate study, providing travel and living expenses for use in attending a scientific summer school or tutorial workshop in condensed matter …

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