Events at Physics
Events on Monday, February 24th, 2014
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Transport Properties of Strongly Coupled Plasmas
- Time: 12:00 pm - 1:00 pm
- Place: 2241 Chamberlin
- Speaker: Scott Baalrud, University of Iowa
- Host: Cary Forest
- Condensed Matter Theory Group Seminar
- Valleytronics in Silicon: the Principles and the Practice
- Time: 4:30 pm
- Place: Chamberlin 5310
- Speaker: Andre Saraiva, University of Wisconsin
- Abstract: Alternative schemes for information processing are being pursued by the industry. Spintronics - the most prominent candidate for alternative electronics - explores an internal degree of freedom of electrons, namely the spin, in order to encode information. Recent advances in the manipulation of the valley degree of freedom of certain semiconductors are opening the possibility for a third option: Valleytronics. But in order to achieve useful control of valley, large enough valley-orbit induced valley splitting (VS) must be achieved.
We will present three ways to control valleys on a scale higher than 1 meV:
a) in a quantum well, the adoption of a barrier constituted of a layered heterostructure might lead to constructive reflection if the layer thicknesses match the electron wavelength, in analogy with a Bragg mirror ;
b) the disparity between the high valley splitting in a impurity donor potential and the low splitting in a Si/Insulator interface may be harnessed controlling the tunneling between these two states, so that the valley splitting may be controlled digitally ;
c) intrinsic Tamm/Shockley interface states might strongly hybridize with conduction states, leading to a much enhanced valley splitting[4,5], and its contribution to the 2DEG ground state may be experimentally identified .
1. D. Culcer, A. L. Saraiva, Belita Koiller, Xuedong Hu, and S. Das Sarma, PRL *108*, 126804 (2012).
2. L. Zhang, J.-W. Luo, A Saraiva, Belita Koiller, Alex Zunger, Nature Comm. *4*, 2396 (2013)
3. A. Baena, A. L. Saraiva, Belita Koiller, and M. J. CalderA3n, PRB 86, 035317 (2012).
4. K. Takashina, Y. Ono, A. Fujiwara, Y. Takahashi and Y. Hirayama, *PRL* *96, *236801 (2006).
5. A. Saraiva, Belita Koiller and M. Friesen, Phys. Rev. B *82*, 245314 (2010).
6. A. Dusko, A. Saraiva and Belita Koiller, arXiv:1310.6878 (2013).
- Host: Perkins