Mai

What role does crystalline lattice play in the emergence of electronic order? Following our previous work on the excitonic soft mode and emergent coherence of Ta2NiSe5 (WebLink: npj Quantum Materials 6, 52 (2021) ArXiv Link: arXiv:2007.07344 PDF: File), we explore the lattice dynamics of the excitonic insulator candidate family Ta2Ni(Se1-xSx)5 by means of Raman scattering. Strong interactions between optical phonons …

Research Update: lattice dynamics of excitonic insulator Ta2Ni(Se1-xSx)5 Read More »

Following our previous work on the excitonic soft mode and emergent coherence of Ta2NiSe5 (WebLink: npj Quantum Materials 6, 52 (2021) ArXiv Link: arXiv:2007.07344 PDF: File), we study the effect of sulfur doping on the excitonic ground state. The critical excitonic fluctuations diminish with the sulfur doping x, and eventually shift to high energies, which is characteristic of a quantum …

Research Update: electronic phase diagram of excitonic insulator Ta2Ni(Se1-xSx)5 Read More »

What is the relationship between the nature of a spin liquid (SL) and the crystal-field (CF) ground state? Layers of Tb ions in the ferroelectric insulator TbInO3 have been proposed to hold a two-dimensional SL ground state. By inelastic light-scattering experiments we demonstrate that the Tb ions have a non-Kramers doublet ground state, which supports …

Research Update: non-Kramers doublet ground state of the triangular-lattice spin-liquid candidate TbInO3 Read More »

We study the thermodynamic and high-magnetic-field properties of the magnetic insulator Ba5CuIr3O12, which shows no magnetic order down to 2 K, consistent with a spin-liquid ground state. While the temperature dependence of the magnetic susceptibility and the specific heat shows only weak antiferromagnetic correlations, we find that the magnetization does not saturate up to a …

New Paper Published: Random singlet state in Ba5CuIr3O12 single crystals Read More »

S.-F. Wu, A. Almoalem, I. Feldman, A. Lee, A. Kanigel, G. Blumberg We study Fe1+yTe0.6Se0.4 multi-band superconductor with Tc = 14K by polarization-resolved Raman spectroscopy. Deep in the superconducting state, we detect pair-breaking excitation at 45cm−1 (2∆ = 5.6 meV) in the XY (B2g) scattering geometry, consistent with twice of the super- conducting gap energy …

New Paper Published: Superconductivity and phonon self-energy effects in Fe1+yTe0.6Se0.4 Read More »

Richard L. Greene Dissertation Award recognizes doctoral thesis research of exceptional quality and importance in experimental condensed matter or experimental materials physics. Sean’s excellent dissertation, “Collective excitations in the antisymmetric channel of Raman spectroscopy”, is an outstanding contribution to the physics society.

Authors: W.-L. Zhang, Y. Song, W.-Y. Wang, C.-D. Cao, P.-C. Dai, C.-Q. Jin, and G. Blumberg Abstract: We use polarization-resolved Raman scattering to study lattice dynamics in  NaFe0.53Cu0.47As single crystals. We identify four A1g phonon modes, at 126, 172, 183, and 197 cm-1, and four B3g phonon modes at 101, 139, 173, and 226 cm-1(D2h point group). The phonon spectra are consistent …

New Paper Published: Raman scattering study of NaFe0.53Cu0.47As Read More »

Authors:  M.Ye, H.-S.Kim, J.-W.Kim, C.-J.Won, K.Haule, D.Vanderbilt, S.-W.Cheong and G. Blumberg Abstract:  We report ab-initio density functional theory calculation and Raman scattering results to explore the electronic structure of Ba5CuIr3O12 single crystals. This insulating iridate, consisting of face-sharing IrO6 octahedra forming quasi-one-dimensional chains, cannot be described by the local jeff = 1/2 moment picture commonly …

Covalency-driven collapse of strong spin-orbit coupling in face-sharing iridium octahedra Read More »