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SUMMARY:Topological Kondo Insulators and SmB6: magnetism meets topology. -
Piers Coleman\, Center for Materials Theory\, Rutgers\, New Jersey\, USA
DTSTART:20140424T131500Z
DTEND:20140424T141500Z
UID:TALK52200@talks.cam.ac.uk
CONTACT:Dr G Moller
DESCRIPTION:The electrons in Heavy fermion materials are subject to spin-o
rbit coupling nteractions that greatly exceed their Kinetic energy. It ha
s long been known that the spin orbit coupling stablizes new kinds of heav
y fermion metals\, superconductors and "Kondo insulators" against the comp
eting state of magnetism. I will discuss the latest realization that spin
orbit coupling can changing the topology of Kondo insulators\, sometimes
giving rise to Topological Kondo insulators [2\,3] with surface Dirac cone
s. We'll specifically discuss SmB6\, a KI discovered 45 years ago\, predic
ted to be topological in 2010 [2]\, and tentatively confirmed to be so in
a series of experimental studies of the past year [3\,4\,5]. I'll discuss
a simple model for a topological Kondo insulator and briefly introduce the
most recent measurements\, including ARPES\, de Haas van Alphen and weak
antilocalization that appear to support the idea that this is a strongly i
nteracting topological insulator. One of the interesting questions is why
the surface Dirac Cones seem to involve light fast electrons. I will discu
ss this in the context of "Kondo Band Bending"- the modification of the Ko
ndo effect by the surface.\n\n[1] Work supported by DOE grant DE-FG02-99ER
45790.
\n[2] M. Dzero et al. Phys. Rev. Lett. 104\, 106408 (2010).
\
n[3] S. Wolgast et al\, PRB 88\, 18\, 180405\, (2013).
\n[4] D. J. Kim
et al\, Sci. Rep. 3\, 3150\, (2013).
\n[5] G. Li et al\, arXiv:1306.52
21 (2013).
\n[6] S. Thomas et al. arXiv:1307.4133 (2014).
\n[7] V. A
lexandrov & P. Coleman\, arXiv:1403.6819 (2014).
LOCATION:TCM Seminar Room\, Cavendish Laboratory
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