It has been a long time without face-to-face meetings. The APS March meeting was very welcome to catch up with the community and keep up to date about latest results. A few highlights from my own perspective:
- Jenny Hoffman (Harvard) presented “acoustic metamaterials”: 3D printed graphene lattice shaped cavities in which air is flown. Interestingly, she is able to measure the acoustic resonance in each lattice point which turns out, in Fourier space, to be analoguous of the band structure of graphene. This could help theoreticians, when numerical simulations are impossible.
- Philip Kim (Harvard) showed twisted BISCCO layers. He demonstrated that monolayer BISCCO doesn’t lose any of the superconducting properties, and then created high quality junctions when twisting two layers at 45°. The results, notably half-integer Shapiro steps, are impressive, potentially the sign of a d-wave superconductor. In a different talk, Marcel Franz (University of British Columbia) showed that it is a good recipe to engineer topological superconductivity.
- The D65 session provided a good summary of current issues in topological superconductivity, highlighting research directions for potential Majorana fermions. However, I regret that in this realm, retracted papers continue to be cited.
- Haoxin Zhou (UCSB) gave more details about superconductivity in Bernal bilayer and Rhombohedral trilayer graphene and how they found it.
- Jinwon Lee (Leiden) presented an experimental method to distinguish Mott insulators from Band insulators.
- Jiacheng Zhu (Cornell) showed that insulators equipped with graphite gate could show quantum oscillations. This is in fact an artefact coming from the gate. Variations of the gate-induced doping induces resistance oscillations.
- There was a series of talks on STM particularly pedacogical, from Kevin Nuckolls (Princeton) and Stevan Nadj-Perge (Caltech). They were using STM spectroscopy to image superconductivity in multilayer graphene. On a different note, Roland Wiesendanger (Hamburg) used STM to create and probe spin-polarised states. Using a functionalised STM tip, he created Nb 1D wires and observed spectroscopic signatures of Majorana edge states.
- Dacen Waters (University of Washington) showed multiple twisted graphene multilayer devices in different configurations. Stacks made of 2L twisted with 3L sheets seem to be particularly interesting, but I have the feeling that everything that could be tried in graphene multilayers has already been done. The community needs to move to the next big thing, and that is certainly not twisted graphene.
- The two sessions on topological superconductivity on Friday were nice, but I regret the lack of consistency at the end of the schedule.
Finally, it was nice to meet a lot of people and see former colleagues and collaborator again. It looked like the audience was very young, with multiple PhD students and postdocs giving invited talks.
This was a hybrid meeting and a number of talks were pre-recorded. I’ll have a look again at these, but it doesn’t seem to be a working for the in-person meeting. People would prefer go to an in-person talk, leaving the video play in an empty room. There are, however, nice counter-examples. Other societies (MRS for example) now hold two meetings: 1 virtual and one in-person. I think it would be the way to go from now on.