BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-2004 DTSTART:20110414T150000Z DURATION:PT1H0M0S DTSTAMP:20260310T212340Z 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 END:VEVENT END:VCALENDAR