Skip to content Skip to main navigation Report an accessibility issue

Researching the Unexpected

Humans are creatures of habit. They enjoy consistency and can be resistant to change and disorder, and how a person responds to that disorder can reveal a bit about them. Consider a coffee shop during morning rush hour. Patrons line up and give their orders one by one. The orders are then filled by employees as they are received. Now imagine a new customer enters the store, sees the line and chooses to walk to the front of it. An observer would likely see several different reactions from the customers in line. One may huff, one may politely attempt to correct the offense and one may yell, revealing a bit of their personality in their behavior.

In research, investigators often find themselves studying disorder to develop a clearer understanding of a subject. Such is the case with Dr. Steven Johnston of the University of Tennessee’s department of physics. Johnston’s team is studying the orbital freedom of electrons in iron pnictide superconductors.

Now in its second year of funding, Johnston’s Joint Directed Research Development (JDRD) project began with the creation of a computational model. With that model completed and generating meaningful results, Johnston is moving forward by introducing atoms with impurities and observing the behavioral changes of the affected electrons.

johnston-final-solo“This year now that we know our method works very well, we’re starting to forge out into new areas that haven’t been tackled yet. One of the goals was to be able to simulate these electrons on extended clusters,” said Johnston. “The ultimate goal there was that by treating everything on a very extended cluster we could do things like disorder or impurity effects. This is something that can’t be handled by every conventional approach that’s been applied to this problem to date.“


Johnston’s team hopes their methodology and use of extended clusters will provide more detailed and accurate information than previous studies.

Data gathered by Johnston’s team has been shared with his Oak Ridge National Laboratory (ORNL) partner, Dr. Thomas Maier, whose work focuses on neutron scattering in strongly correlated and disordered materials. Additionally, several new collaborations have begun between Johnston and Maier as a result of the JDRD project.