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PRODID:UW-Madison-Physics-Events
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UID:UW-Physics-Event-2004
DTSTART:20110414T150000Z
DURATION:PT1H0M0S
DTSTAMP:20240329T103439Z
LAST-MODIFIED:20110411T130922Z
LOCATION:5310 Chamberlin
SUMMARY:Interface engineering in epitaxial oxide heterostructures\, R.
G. Herb Condensed Matter Seminar\, Alex Demkov\, University of Texas
at Austin
DESCRIPTION:The astounding progress of recent years in the area of oxi
de deposition has made possible the creation of oxide heterostructures
with atomically abrupt interfaces. The ability to control the length
scale\, strain\, and orbital order in these materials structures offer
s a uniquely rich toolbox for condensed matter physicists. Because the
oxide layers are very thin\, the physics is often controlled by the i
nterface. The electronic properties of oxide interfaces are governed b
y a subtle interplay of many competing mechanisms such as polar catast
rophe\, Jahn-Teller coupling\, electron correlation\, defects\, and ph
ase stability. It is not clear which\, if any\, of these systems will
find applications in future high-tech devices. However\, they undoubte
dly hold tremendous promise\, particularly when integrated with conven
tional semiconductors such as Si.
\n
\nIn this talk I will rev
iew our recent results in theoretical modeling and experimental realiz
ation of several epitaxial oxide heterostructures. I will set the stag
e with a brief discussion of the n-type conductive SrTiO3/L
aA1O3 interface [1]. The origin of charge in this nominally
insulating system is still under intense debate\, and the difficultie
s are\, in my opinion\, generic to the entire field. Our theoretical r
esults are consistent with the originally proposed polar catastrophe m
odel\, should the field be indeed stabilized in polar LaA1O3. However\, our results indicate that this may be difficult to achiev
e. I then will discuss extrinsic magnetoelectric coupling at the inter
face of a perovskite ferroelectric and conventional ferromagnet [2\,3]
. In contrast with the previously proposed models\, the structure we c
onsider offers the robust\, linear coupling. If time permits\, I will
describe our efforts to achieve the monolithic integration of ferromag
netic oxide LaCoO3(LCO) and silicon for possible applicatio
ns in spintronics [4]. The integration is achieved via the single crys
tal SrTiO3 (STO) buffer epitaxially grown on Si. The interm
ediate spin state is stabilized by epitaxial strain at the STO/LCO int
erface.
\n
\n1. J. K. Lee and A. A. Demkov\, Phys. Rev. B 7
8\, 193104 (2008).
\n2. T. Cai\, Q. Niu\, J. K. Lee\, Na Sai\,
and A. A. Demkov\, Phys. Rev. B 80\, 140415(R) (2009).
\
n3. J. K. Lee\, Na Sai\, T. Cai\, Q. Niu and A. A. Demkov\, Phys. Re
v. B 81\, 144425 (2010).
\n4. A. Posadas\, M. Berg\, H. Seo
\, D. J. Smith\, H. Celio\, A. P. Kirk\, D. Zhernokletov\, R. M. Walla
ce\, A. de Lozanne\, and A. A. Demkov\, Appl. Phys. Lett. 98\,
055104 (2011).
\n
URL:https://www.physics.wisc.edu/events/?id=2004
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