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Executive Director Megan Wheeler and Director of External Affairs & Fellowship Matt Goode of the Schmidt Science Fellows, a Google program, visited CNAM yesterday. They met with Director Johnpierre Paglione and Nicholas P. Butch to learn more about Wesley Fuhrman's work in our center.
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Congratulations to Ph.D. candidate Daniel Campbell! He is one of the recipients of the Ann G. Wylie Dissertation Fellowship. The Ann G. Wylie Dissertation Fellowship is part of the Graduate School's Semester Dissertation Fellowship program. This program provides support to University of Maryland doctoral candidates who are in the latter stages of writing their dissertations.
Daniel Campbell is investigating the synthesis and characterization of bulk quantum materials, including iron-based superconductors and transition metal pnictide materials, rare-earth based compounds, and transition metal dichalcogenides.
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The Postdoc Award goes to Jen-Hao Yeh for his presentation on "Reduction of Cavity Photon Dephasing for Superconducting Qubits"
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A collaboration of CNAM members including Richard L. Greene and Tarapada Sarkar, together with researchers from SLAC, ESRF, CNR-Spin and Binghamton University, has been exploring the Three-dimensional collective charge excitations in electron-doped copper oxide superconductors.
High-temperature copper oxide superconductors consist of stacked CuO2 planes, with electronic band structures and magnetic excitations that are primarily two-dimensional, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state, within a limited range of momenta accessible by optics. In this research, we used resonant inelastic X-ray scattering to RIXS explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides reveals their charge origin, that is, without mixing with magnetic components. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighboring CuO2 planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought ‘acoustic plasmon’, which is a branch of distinct charge collective modes predicted for layered systems and argued to play a substantial part in mediating high-temperature superconductivity.
This work is now published October 31, 2018 in Nature. https://www.nature.com/articles/s41586-018-0648-3/#auth-1