Authors: H.-H. Kung, S. Ran, N. Kanchanavatee, V. Krapivin, A. Lee, J.A. Mydosh, K. Haule, M.B. Maple, and G. Blumberg Abstract: In URu2Si2 two types of staggered phases involving long range ordering of the uranium-5f electrons compete at low temperature when a critical parameter x is tuned, where x can be chemical substituent concentration, pressure …

Analogy between the `hidden order’ and the orbital antiferromagnetism in URu2Si2 Read More »

Authors: S.-F. Wu, W.-L. Zhang, D. Hu, H.-H. Kung, A. Lee, H.-C. Mao, P.-C. Dai, H. Ding, P. Richard and G. Blumberg Abstract: We use electronic Raman scattering to study the low-energy excitations in BaFe2(As0.5P0.5)2 (Tc≈16 K) samples. In addition to a superconducting pair breaking peak (2Δ=6.7 meV) in the A1g channel with a linear …

Collective excitations of dynamic Fermi surface deformations in BaFe2(As0.5P0.5)2 Read More »

Authors: W.-L. Zhang, Athena S. Sefat, H. Ding, P. Richard, and G. Blumberg Abstract: We use polarized Raman scattering to study the structural phase transition in EuFe2As2, the parent compound of the 122-ferropnictide superconductors. The in-plane lattice anisotropy is characterized by measurements of the side surface with different strains induced by different preparation methods. We …

Stress-induced nematicity in EuFe2As2 studied by Raman spectroscopy Read More »

Authors: W.-L. Zhang, Z. P. Yin, A. Ignatov, Z. Bukowski, Janusz Karpinski, Athena S. Sefat, H. Ding, P. Richard, and G. Blumberg Abstract: We present a polarization-resolved and temperature-dependent Raman scattering study of AFe2As2(A=Ca,Eu). In the spin-density-wave phase, spectral weight redistribution is observed in the fully symmetric and nonsymmetric scattering channels at different energies. An …

Raman scattering study of spin-density-wave-induced anisotropic electronic properties in AFe2As2 ( A = Ca, Eu) Read More »

Authors: Daixiang Mou, Aashish Sapkota, H.-H. Kung, Viktor Krapivin, Yun Wu, A. Kreyssig, Xingjiang Zhou, A. I. Goldman, G. Blumberg, Rebecca Flint, Adam Kaminski Abstract: We use Angle Resolved Photoemission Spectroscopy (ARPES), Raman spectroscopy, Low Energy Electron Diffraction (LEED) and x-ray scattering to reveal an unusual electronically mediated charge density wave (CDW) in K0.9Mo6O17. Not …

Discovery of an unconventional charge density wave at the surface of K0.9Mo6O17 Read More »

Authors: V. K. Thorsmølle, M. Khodas, Z. P. Yin, Chenglin Zhang, S. V. Carr, Pengcheng Dai, and G. Blumberg Abstract: The multiband nature of iron pnictides gives rise to a rich temperature-doping phase diagram of competing orders and a plethora of collective phenomena. At low dopings, the tetragonal-to-orthorhombic structural transition is closely followed by a spin-density-wave …

Critical quadrupole fluctuations and collective modes in iron pnictide superconductors Read More »

Authors: H.-H. Kung, R. E. Baumbach, E. D. Bauer, V. K. Thorsmølle, W.-L. Zhang, K. Haule, J. A. Mydosh, G. Blumberg Abstract: A second-order phase transition in a physical system is associated with the emergence of an “order parameter” and a spontaneous symmetry breaking. The heavy fermion superconductor URu2Si2 has a “hidden order” (HO) phase below …

Chirality density wave of the ‘hidden order’ phase in URu2Si2 Read More »

Authors: B. S. Dennis, M. I. Haftel, D. A. Czaplewski, D. Lopez, G. Blumberg and V. A. Aksyuk Abstract: Highly confined optical energy in plasmonic devices is advancing miniaturization in photonics. However, for mode sizes approaching ≈10 nm, the energy increasingly shifts into the metal, raising losses and hindering active phase modulation. Here, we propose a …

Compact nanomechanical plasmonic phase modulators Read More »