APS March Meeting 2012
Volume 57, Number 1
Monday–Friday, February 27–March 2 2012;
Boston, Massachusetts
Session A19: Invited Session: New Correlated Electron Physics Using Scanning Tunneling Microscopy and Other Probes
8:00 AM–11:00 AM,
Monday, February 27, 2012
Room: 253AB
Sponsoring
Unit:
DCMP
Chair: Abhay Pasupathy, Columbia University
Abstract ID: BAPS.2012.MAR.A19.4
Abstract: A19.00004 : Defects in Heavy-Fermion Materials: Unveiling Strong Correlations in Real Space*
9:48 AM–10:24 AM
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Abstract
Author:
Dirk Morr
(University of Illinois at Chicago)
Heavy-fermion materials exhibit a plethora of puzzling phenomena
which are believed to arise from the competition between Kondo screening and antiferromagnetic
ordering. The microscopic origin of these phenomena, such as the non-Fermi-liquid
properties observed in the quantum critical region, is still a topic of debate. Recent groundbreaking scanning tunneling spectroscopy (STS) experiments
[1-4] have shed new light on this debate by providing important
insight into the electronic and magnetic structure of heavy fermion
materials.
In this talk, I review some recent progress made in our theoretical understanding of the
differential conductance, dI/dV and the resulting quasi-particle interference (QPI) patterns [5-7], observed in these experiments.
In particular, I will demonstrate that
defects in heavy-fermion materials provide an unprecedented
opportunity to disentangle electronic correlations arising from Kondo screening, and antiferromagnetic
correlations between the magnetic moments by inducing perturbations in the electronic and magnetic structure that
exhibit characteristically different spatial patterns. The spatial extent of these perturbations
grows with the strength of the magnetic interactions, and thus directly reflects the degree of
correlations [5]. In addition, I show that non-magnetic defects (Kondo holes) in heavy fermion materials can give rise to the formation of an impurity bound.
Our prediction of spatial hybridization oscillations and the formation of an impurity bound state were recently confirmed by
STS experiments [4]. Moreover, I will demonstrate that QPI spectroscopy, utilizing spatial oscillations in the LDOS
induced by defects, does not only provide important insight into the electronic structure of heavy fermion materials, but
also in the entanglement of electronic and magnetic states [6,7]. Finally, the strongly correlated nature of
heavy-fermion materials leads to a highly non-linear quantum interference between defects, and the
creation of order from disorder. These results provide unique insight into the spatial complexity of heavy fermion materials.
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[1] A.R. Schmidt et al., Nature 465, 570 (2010).
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[2] P. Aynajian et al., PNAS 107, 10383 (2010).
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[3] S. Ernst et al., Nature 474, 362 (2011).
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[4] M. Hamidian et al., PNAS 108, 18233 (2011).
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[5] J. Figgins and D.K. Morr, Phys. Rev. Lett. 107, 066401 (2011).
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[6] J. Figgins and D.K. Morr, Phys. Rev. Lett. 104, 187202 (2010).
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[7] T. Yuan, J. Figgins, and D.K. Morr, arXiv:1101.2636.
*This work was performed in collaboration with J. Figgins and T. Yuan, and was supported by the U.S. Department of Energy under Award No. DE-FG02-05ER46225
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.MAR.A19.4