APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014;
Denver, Colorado
Session M39: Invited Session: SmB6: A Possible Topological Kondo Insulator
11:15 AM–2:15 PM,
Wednesday, March 5, 2014
Room: Mile High Ballroom 2A-3A
Sponsoring
Unit:
DCMP
Chair: Zach Fisk, University of California, Irvine
Abstract ID: BAPS.2014.MAR.M39.4
Abstract: M39.00004 : Topological Kondo Insulator (TKI) and related candidate materials: High-resolution ARPES studies
1:03 PM–1:39 PM
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Abstract
Author:
M. Zahid Hasan
(Princeton Univ)
In this talk, I plan to present ARPES (synchrotron and laser-based) studies
of several mix valence and Kondo insulator phenomena in some of the rare
earth heavy fermion compounds in connection to their non-trivial topology of
band structures. Focus will be on SmB6 which has been predicted to be a TKI
recently. By combining low-temperature and high energy-momentum resolution
of the laser-based ARPES technique, for the first time, we accessed the
surface electronic structure of the anomalous conductivity regime. At low T,
we observe in-gap states within a 4 meV energy window of the Fermi level,
which lie clearly within the bulk insulating gap. The in-gap states are
found to be suppressed and eventually disappear, as the temperature is
raised in approaching the coherent Kondo lattice hybridization (30 K), which
proves that the in-gap states strongly depend on the existence of Kondo
lattice hybridization and the effective Kondo gap, in agreement with their
theoretical predicted origin of topological surface states within the Kondo
insulating gap . Our Fermi mapping at the energy corresponding to these
in-gap states shows distinct Fermi pockets that enclose the three Kramers'
points the surface Brillouin zone, which are remarkably consistent with the
theoretically predicted topological surface Fermi surface in the topological
Kondo insulating phase within the level of energy resolution. The observed
Fermi surface topology of the in-gap states, their temperature dependence
across the transport anomaly and Kondo lattice hybridization temperatures,
as well as their robustness against repeated thermal recycling, collectively
not only provide a unique insight illuminating the nature of the residual
conductivity anomaly but also serve as a strong experimental evidence to the
predicted topological Kondo insulator phase. I also plan to present results
on YbB6 and YbB12 both of which are mix valence compounds. This work is in
collaboration with \textbf{Madhab Neupane}, N. Alidoust, S.-Y. Xu, T. Kondo,
Y. Ishida, D.-J. Kim, Chang Liu, I. Belopolski, T.-R. Chang, H.-T. Jeng, T.
Durakiewicz, L. Balicas, H. Lin, A. Bansil, S. Shin and Z. Fisk and
primarily supported by U.S. DOE and Princeton University.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.M39.4