Bill Atkinson
Theoretical and Computational Simulations of Quantum Materials

Research

The fundamental properties of all materials---such as their colour, hardness, or electrical conductivity---are determined, in the end, by the laws of quantum mechanics.  Quantum materials are different because quantum mechanics adds an extra twist to the usual story.  This can happen for many reasons, for example because of confined geometry, topological effects, or collective behaviour, but ultimately it always comes back to the fact that electrons (and sometimes atoms!) behave like waves, and not particles. 

In recent years, I have been working with students and collaborators on developing models for two families of quantum materials:  high temperature superconductors and strontium titanate interfaces. 

  • If you want to know more, an almost-complete list of my papers can be found here.

  • Here is the talk I was supposed to give at the 2020 APS March Meeting in Denver, before it was cancelled.

Strontium titanate
is an old material that has recently been rediscovered by the physics community.  One of its truly fascinating features is that it is almost a ferroelectric; almost anything you do to this material (for example, replacing 16O with slightly heavier 18O) turns it into a ferroelectric.  From a physics point of view, it means that strontium titanate's electronic and physical properties are shaped by a quantum critical point that separates the ferroelectric and nonferroelectric phases.  The question that we have been asking in my group is how this quantum critical point shows up in the electronic properites of strontium titanate devices.  Two of the more surprising answers can be found here and here

 

High temperature superconductors are remarkable because strong correlations amongst electrons generate a variety of exotic phases of matter, including antiferromagnetic, charge density wave, nematic, and (of course) superconducting phases.  I am really interested in two questions:  what are the conditions that allow these phases to form?, and what tips the balance between the different phases in different materials? Want to know more?  Here's a nice discussion of some practical aspects of superconductors.