Wednesday, September 22, 2021

DOE Experimental Condensed Matter PI meeting, Day 3

Here are some tidbits from the last day of this year's meeting.  (I didn't really get to see the other posters in my own poster session, so apologies for missing those.  For the curious:  the meeting attendees alternate between posters and 15 minute talks from year to year.)

• It's been known for a while that combining magnetism with topological insulator materials can lead to a rich phase diagram.  Tuning composition is a powerful tool.  Likewise, the van der Waals nature of these systems mean that it's possible to look systematically through a family of related materials.
• Tuning composition in flat-band kagome metals is also of interest.
• I had not appreciated just how important specific crystal growth approaches (e.g., rapid quenching vs. slow annealed cooling) are to the properties of some magnetic/topological materials, such as Fe5GeTe2.
• Strain can be a powerful tool for tuning electronic topology in some materials such as ZrTe5, and driving certain phonon modes via laser offers the potential of controlled switching of topological properties.
• Quantum oscillations (e.g., magnetization as a function of 1/H) are a conventional way to learn about Fermi surfaces, and it is always bizarre when that kind of response shows up in a correlated material that is nominally an insulator, or in thermal transport but not electrical transport.
• Speaking of quantum oscillations in insulators, how about thermal transport in the spin liquid phase of $\alpha$-RuCl3?  Looks like some kind of bosonic edge mode is responsible.
• If transition metal dichalcogenides are starting to bore you, perhaps you'd be more interested in trichalcogenides, which can be grown as individual 1D chains within carbon and boron nitride nanotubes.
Thanks to everyone for making the meeting enjoyable and informative, even if we couldn't get together in a random Marriott in Maryland this time.