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HEMI Colloquium: Collin Broholm

February 5, 2016 @ 3:30 pm - 4:30 pm

Strange Magnetism Exposed by Neutron Scattering

Collin Broholm*
Department of Physics and Astronomy and
Institute for Quantum Matter, The Johns Hopkins University

A radically different form of magnetism defined by quantum entanglement is explored using neutron scattering. Starting from illustrative one-dimensional examples, I discuss recent experiments that probe magnetic excitations in two and three-dimensional frustrated quantum magnets. In analogy with atomic positions in superfluid 4He, atomic scale magnetic dipoles in these materials exist in a state of quantum superposition near the absolute zero temperature. While there is no static magnetic order to distinguish such materials they host exotic emergent quasi-particles that scatter neutrons. The potential relevance of the quantum spin liquid to high temperature superconductivity shall be illustrated through our recent quantitative and spatially resolved measurements of the superconducting condensation energy in Fe1+ySexTe1-x [3].

*supported by the US Department of Energy, office of Basic Energy Sciences, Division of Material Sciences and Engineering under grant DE-FG02-08ER46544.

Seminar will be held in Malone G33/35.