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Materials Science Research Lecture

Wednesday, November 10, 2021
4:00pm to 5:00pm
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Noyes 147 (J. Holmes Sturdivant Lecture Hall)
Quantum Disorder in the Magnetism of Spin-Orbit Entangled AMO2 Delafossites (A=alkali metal, M=metal)
Stephen Wilson, Professor, Materials Science Department, University of California, Santa Barbara,

NOTE: At this time, in-person Materials Research Lectures are open to all Caltech students/staff/faculty/visitors with a valid Caltech ID. Outside community members are welcome to join our online webinar.

Webinar Link:

https://caltech.zoom.us/j/83276652110

Webinar ID: 832 7665 2110

Abstract:

Magnetic states defined by intrinsic quantum disorder are a long-standing fascination in condensed matter physics due to their potential to harbor unique, nonlocal forms of order and emergent symmetries. Various types of quantum spin liquid states are predicted to arise in geometrically frustrated magnets when decorated with quantum spins, and there has been a recent resurgence in identifying these states in canonical triangular lattice antiferromagnets. Specifically, for moments whose spin state becomes entangled with the orbital degree of freedom, native spin liquid-like states arise, contrary to long-held predictions of conventional order in the spin-only quantum limit. Here I will present some of our recent work exploring quantum disorder within the magnetism of triangular lattice delafossite-like compounds of the form AMO2 (A=alkali ion, M=metal ion). When the M-site is chosen to host a spin-orbit entangled wavefunction with Jeff=1/2, highly unconventional magnetic ground states arise that lack long-range order or static moment freezing. I will present an overview of several materials that host this behavior and hopefully motivate future exploration of the fascinating magnetism that arises in these materials platforms.

More about the Speaker:

Stephen Wilson received his Ph.D. in Physics from the University of Tennessee in 2007 and then worked as a postdoc in the Materials Science Division at Lawrence Berkeley National Lab through 2009. He served on the faculty of the Physics Department at Boston College from 2010-2014, after which he joined the faculty of the Materials Department at UC Santa Barbara. He is currently serving as Professor and Associate Chair of Materials at UCSB where he also co-directs the NSF's Quantum Foundry. Stephen's research program focuses on the synthesis and advanced characterization of novel quantum materials, ranging from unconventional superconductors to quantum magnets.

For more information, please contact Jennifer Blankenship by email at jennifer@caltech.edu.