Wednesday, March 06, 2019

APS March Meeting, Day 2

A random selection from Day 2:

  • Thomas Silva at NIST gave a fun talk about some experiments using the linac coherent light source.  Using pump/probe time-resolved x-ray diffraction, they discovered some surprising acoustic modes in thin, polycrystalline metal films, with systematics suggesting that they might be seeing localization of phonons due to scattering off grain boundaries.
  • Along those lines, Gang Chen of MIT spoke about seeing reductions in thermal conductivity due to phonon localization.  His group was working with semiconductor superlattices, with little ErAs nanodots embedded in a disordered way at the superlattice interfaces.  They see systematics in the thermal conductivity that suggest that they are seeing Anderson localization of the heat-carrying phonons.  
  • I stopped by the session on conveying physics to a popular audience, and caught most of the talk by Allison Eck chock full of advice for would-be science writers, and a skyped-in talk by Sean Carroll about podcasting.  The depressing truth: If I really want to expand my audience, I should probably join twitter.  (The problem is, that's a conversational medium and I don't see how I could do it well given everything else.)
  • Abe Nitzan gave a prize talk that was a nice overview of the last decade's work on understanding electrons, photons, and phonons in molecular junctions.
  • I spent much of the afternoon at this session about the copper oxide superconductors.  Dan Dessau's talk primarily about this paper showed the capabilities of a new technique in analyzing angle-resolved photoemission data, to figure out the actual spatial shape of Cooper pairs in these systems. My collaborator Ivan Bozovic spoke (similar to this), showing the power of his tremendous MBE growth approach, able to create epitaxially perfect materials smoothly and systematically spanning the whole doping range.  The other talks in the session were also very interesting.

4 comments:

Anonymous said...

The talk by I. Bozovic was insane and incredibly valuable to the field of oxides. I have a really hard time imagining any institution allowing a single researcher to spend over a decade on the same problem and growing thousands of the same type of films to measure the cuprate phase diagram as carefully as he did. I wonder how science would be different with more careful/thorough experiments like this, instead of chasing the quickest publication.

Douglas Natelson said...

Anon, that film quality is why I'm collaborating w/ him. I agree with your broader point about taking time to do long, careful work -as someone who came up through the go-go days of "nano", I think the tendency of the last 15-20 years to do flag planting experiments and then move on is not good for the overall health of the field. One positive of the tenure system is that it's supposed to free people up to do longer, more ambitious projects; there is then tension with the standard funding process and publication dynamic.

Anonymous said...

Regarding the talk by I. Bosovic last week, I was very impressed by the work, but was disturbed by some of the comments of the audience afterwards. Many felt that it is boring to spend so much effort on a single problem and out of touch with modern scientific progress. I don't like that way of thinking, we need both breakthroughs and systematic tedious work.

Douglas Natelson said...

Anon@10:08, it's not that uncommon that someone either with a unique, specialized measurement technique or with a materials growth focus spends a long time on optimizing some system. Loren Pfeiffer has spent 25+ years growing GaAs heterostructures.