APS March Meeting, Day 2

Another complicated day meant another selection of talks.  It's great that the talks are recorded so that (at least for now) I can go back and watch others that I missed, but somehow watching talks on screen is just as tiring if not moreso than watching them at a convention center.  At least I'm not crammed into a tiny room with 100 other people carrying backpacks, jackets, etc. and struggling to see the screen.

Some highlights:

• Silke Bühler-Paschen from TU Wien gave a nice talk about the Weyl-Kondo semimetal Ce3Bi4Pd3.  This is an example of a topologically interesting material that has strong electronic correlations.  Rather analogous to the situation in heavy fermions, where the correlations flatten the bands and renormalize the electron effective mass to be very large, in this case the Weyl nodes and dispersion of the topological states remain but the dispersion is strongly renormalized.  Another signature of the correlations is the large (renormalized) size of the spontaneous Hall effect in this system.
• Richard Silver from NIST gave a clear presentation about advances in creating atomically precise devices based on individual phosphorus dopants in silicon.  Recent reviews are here and here.  They are making strong progress toward being able to implement quantum simulations of things like the Hubbard model in arrays of sites, though disorder is a major challenge.  A related talk was presented yesterday by Shashank Misra from Sandia.
• There was an interesting session about signatures of the strange metal in both iron pnictide and cuprate superconductors.  This ties in with ideas about the demise of quasiparticles and the possibility of "incoherent" charge-carrying excitations in these systems.  Aharon Kapitulnik ended the session looking at thermal transport in the high temperature limit of these materials, as strange metallicity (linear-in-T resistivity) crosses into bad metallicity (resistivity above the Mott-Ioffe-Regel limit), and concluding that neither electrons nor phonons are well-defined quasiparticles in that limit.  
• Harold Hwang gave an overview and update on the growth of the cuprate-analog infinite layer nickelate material Nd0.8Sr0.2NiO2.  This included stabilization of films by encapsulating them in SrTiO3 during growth, understanding the electronic structure further, and expanding this family of materials.
• The Phys Rev session was also very good, though I only caught pieces - the talks by Sachdev and Marcus were both fun.  The latter did a good job emphasizing the key role of materials in pursuing the goal of engineering topologically nontrivial superconductivity in superconductor/semiconductor hybrid structures.

Tomorrow my work schedule will be more of a constraint, so my writeup will likely be late and a bit sparse.