BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-3300 DTSTART:20140224T223000Z DURATION:PT1H0M0S DTSTAMP:20260313T140033Z LAST-MODIFIED:20140210T151218Z LOCATION:Chamberlin 5310 SUMMARY:Valleytronics in Silicon: the Principles and the Practice\, Co ndensed Matter Theory Group Seminar\, Andre Saraiva\, University of Wi sconsin DESCRIPTION:Alternative schemes for information processing are being p ursued by the industry. Spintronics - the most prominent candidate for alternative electronics - explores an internal degree of freedom of e lectrons\, namely the spin\, in order to encode information. Recent ad vances in the manipulation of the valley degree of freedom[1] of certa in semiconductors are opening the possibility for a third option: Vall eytronics. But in order to achieve useful control of valley\, large en ough valley-orbit induced valley splitting (VS) must be achieved.
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\nWe will present three ways to control valleys on a scale high er than 1 meV:
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\na) in a quantum well\, the adoption of a b arrier constituted of a layered heterostructure might lead to construc tive reflection if the layer thicknesses match the electron wavelength \, in analogy with a Bragg mirror [2]\;
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\nb) the disparity between the high valley splitting in a impurity donor potential and th e low splitting in a Si/Insulator interface may be harnessed controlli ng the tunneling between these two states\, so that the valley splitti ng may be controlled digitally [3]\;
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\nc) intrinsic Tamm/Sh ockley interface states might strongly hybridize with conduction state s\, leading to a much enhanced valley splitting[4\,5]\, and its contri bution to the 2DEG ground state may be experimentally identified [6].< br> \n
\n1. D. Culcer\, A. L. Saraiva\, Belita Koiller\, Xuedong H u\, and S. Das Sarma\, PRL *108*\, 126804 (2012).
\n2. L. Zhang\, J.-W. Luo\, A Saraiva\, Belita Koiller\, Alex Zunger\, Nature Comm. *4 *\, 2396 (2013)
\n3. A. Baena\, A. L. Saraiva\, Belita Koiller\, a nd M. J. CalderA3n\, PRB 86\, 035317 (2012).
\n4. K. Takashina\, Y . Ono\, A. Fujiwara\, Y. Takahashi and Y. Hirayama\, *PRL* *96\, *2368 01 (2006).
\n5. A. Saraiva\, Belita Koiller and M. Friesen\, Phys. Rev. B *82*\, 245314 (2010).
\n6. A. Dusko\, A. Saraiva and Belit a Koiller\, arXiv:1310.6878 (2013). URL:https://www.physics.wisc.edu/events/?id=3300 END:VEVENT END:VCALENDAR