Signatures of a 3D Quantum Liquid Crystal

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Date/Time:Monday, 09 Apr 2018 from 4:10 pm to 5:00 pm
Location:Phys 0003
Phone:515-294-5441
Channel:College of Liberal Arts and Sciences
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Dr. David Hsieh, Caltech

Abstract: In the presence of strong interactions, the fluid of mobile electrons in a metal can spontaneously break the point group symmetries of its underlying host lattice, forming a quantum analogue of a classical liquid crystal. The experimental discovery of 2D quantum liquid crystals (QLCs) was first made nearly 20 years ago in semiconductor heterostructures and has since been reported in many other systems including the copper- and iron-based high-temperature superconductors. However, whether or not a 3D version of a QLC can exist has remained unclear. In this talk, I will present signatures of a 3D QLC in the strongly spin-orbit coupled metallic pyrochore Cd2Re2O7 detected using ultrafast coherent phonon spectroscopy and a recently developed spatially-resolved nonlinear optical polarimetry technique. I will highlight the unusual properties of this 3D QLC that distinguish it from the 2D version and discuss its possible connection to unconventional superconductivity.

Bio: Prof. David Hsieh is an experimental condensed matter physicist whose research focuses on macroscopic quantum electronic phases of matter in solid-state systems. In particular, Prof. Hsieh is interested in developing novel nonlinear optics, time-resolved ultrafast optics and angle-resolved photoemission based spectroscopic probes to search for exotic topological and symmetry-broken quantum phases of matter. Prof. Hsieh earned his B.S in Physics and Mathematics from Stanford University in 2003 and his Ph.D. in Physics from Princeton University in 2009 where he worked on both neutron scattering studies of highly frustrated magnets as well as synchrotron-based spin- and angle-resolved photoemission spectroscopy of topological insulators. From 2009 to 2012, Prof. Hsieh was a Pappalardo Postdoctoral Fellow in Physics at MIT. There he developed several table-top laser-based techniques to study the ultrafast opto-electronic properties of topological insulators and wider classes of correlated spin-orbit coupled systems. He joined the Caltech faculty in 2012. Prof. Hsieh is the recipient of a William L. McMillan Award in condensed matter physics, a Sloan Research Fellowship, a Packard Fellowship in Science and Engineering and a Presidential Early Career Award for Scientists & Engineers.