APS March Meeting 2024, Day 1

There is no question that the meeting venue in Minneapolis is superior in multiple ways to last year's meeting in Las Vegas.  The convention center doesn't feel scarily confining, and it also doesn't smell like a combination of cigarettes and desperation.

Here are a few highlights from the day:

• There was an interesting session about "polar materials", systems that have the same kind of broken inversion symmetry within a unit cell as ferroelectrics; this includes "polar metals" which host mobile charge carriers.  One polar material family involving multiferroic insulators was presented by Daniel Flavián, in which dielectric (capacitance) measurements can show magnetic quantum critical phenomena, as in here and here.  Both sets of materials examined, Rb2Cu2Mo3O12 and Cs2Cu2Mo3O12, show remarkable dielectric effects due to fluctuating electric dipoles, connected to quantum critical points at B-field driven transitions between magnetic ordered states.
• Natalia Drichko from Johns Hopkins showed Raman spectroscopy data on an organic Mott insulator, in which melting charge order is connected to spin fluctuations.
• Pavel Volkov from U Conn discussed doped strontium titanate (STO), an example of an incipient polar metal, and looking at how polar fluctuations might be connected with the mechanism behind the unusual superconductivity of STO. 
• The last talk of that session that I saw was Pablo Jarillo-Herrero giving a characteristically clear presentation about sliding ferroelectricity.  Taking a material like hBN and trying to stack a bilayer with perfect A-A alignment is not energetically favored - it's lower in energy if the two layers shift relative to each other by a third of a lattice parameter, resulting in an out-of-plane electric dipole moment, pointing either up or down depending on the direction of the shift.  Applying a sufficiently large electric field perpendicular to the plane can switch the system - this works on TMDs as well.  Putting a moire bilayer in the mix, and you can get some neat charge ratcheting effects. 
• The session on transport in non-Fermi liquids was fun and informative.  I thought the discussion of possible intrinsic nonlinear transport in strange metals was intriguing.
• I also saw a couple of interesting invited talks (here and here) about experiments that try to use electronic transport in adjacent layers to probe nontrivial magnetic properties of adjacent spin ices.  Very cool.

More tomorrow....