A Nanoscopic Approach to Heavy Fermions: from Kondo droplets to Kondo Holes presented by Professor Dirk Morr of University of Illinois at Chicago

Wednesday, November 14, 2012 - 4:00pm to 5:00pm
Condensed Matter Physics Journal Club

Heavy fermion materials exhibit a plethora of unconventional phenomena, ranging
from a hidden order state to quantum criticality. The key to understanding the microscopic
origin of these phenomena lies in elucidating the complex electronic and magnetic
structure of these materials, a task that has long been proven elusive. Recently, two
groundbreaking, complementary approaches to this problem have been pioneered using
scanning tunneling spectroscopy. In particular, while nanoscopic replicas of heavy-fermion
materials, so-called Kondo droplets, have provided unprecedented control in manipulating
Kondo screening at the nanoscale, defects in heavy fermion materials have been utilized
to explore the nature of the strong correlations in real space.
In this talk, I will present a theoretical discussion of these new approaches and demonstrate
that they allow us to gain exceptional insight into the correlated electronic and
magnetic structure of heavy fermion materials. In particular, I will show that Kondo
droplets provide a unique opportunity to locally study the competition between Kondo
screening and magnetic ordering which are at the heart of the heavy fermion problem.
Moreover, I will demonstrate that defects induce perturbations in the electronic and
magnetic structures that possess characteristically different spatial patterns and directly
reflect the strength of correlations. As a result, it is possible to disentangle electronic and
magnetic correlations in real space.