Making Semiconductors Ferromagnetic: Opportunities and Challenges
|Date/Time:||Monday, 02 Apr 2012 from 4:00 pm to 4:50 pm|
|Location:||Physics Hall Room 5|
Abstract: Introducing ferromagnetism into semiconductors holds out the promise of using the spin of the electron, alongside its charge, for the purpose of increasing the functionality of semiconductor devices. This is the focus of the emerging technology referred to as "spintronics". It has already been demonstrated that III-V semiconductor compounds (e.g., GaAs) can indeed be made ferromagnetic by replacing a fraction of the III-V lattice by substitutional Mn ions to form III1-xMnxV alloys (e.g., Ga1-xMnxAs). The Mn atom enters the III-V lattice as a divalent Mn++ ion, and thus acts both as a magnetic moment and as an acceptor. It is the large concentration of holes generated by the acceptor nature of Mn++ which provides the mechanism for long-range ferromagnetic coupling between the Mn spins. In this talk I will discuss the various methods of preparing such III1-xMnxV alloys; their representative ferromagnetic properties (the Curie temperature, magnetic domains, magnetic anisotropy, etc.); methods of controlling these properties; and the challenges that still need to be overcome in order to bring these properties to a level suitable for practical applications.
Bio: Professional and Academic Essentials: J. K. Furdyna obtained his B.S degree in physics from Loyola University, Chicago, in 1955; and his Ph.D. in experimental solid state physics at Northwestern University in 1960. After two postdoctoral years in Northwestern's Department of Electrical Engineering (1960-62), he joined the M.I.T. Francis Bitter National Magnet Laboratory in 1962. In 1966 he joined the Physics Department at Purdue University as Associate Professor, and was promoted to Professor in 1972. At Purdue he served as Director of the Materials Research Laboratory from 1982 to 1985. In 1987 he was appointed to the Marquez Endowed Chair of Physics at the University of Notre Dame. His current research interests include materials preparation of semiconductors by molecular beam epitaxy; optical spectroscopy of semiconductor super lattices, quantum wells, and lower-dimensional structures (quantum dots and wires); short-wavelength optoelectronics and light emitting devices; and research on high efficiency solar cells. During his professional career Furdyna has been Ph.D. advisor to 30 graduate students, and sponsored 16 post-doctoral scholars.
Honors and Distinctions: J. K. Furdyna is Fellow of the American Physical Society and of the Institute of Physics (UK). In 2008 he was selected as "Outstanding Referee" by the American Physical Society. For the totality of his scientific accomplishments he was awarded doctorates honoris causa by Warsaw University in October 2002, and by Purdue University in May 2007. In 2009 he was awarded the Nicolaus Copernicus Medal by the Polish Academy of Sciences.
Synergistic activities and collaborators: J.K. Furdyna collaborates with colleagues in at least 35 other institutions, and has provided both materials and intellectual input toward Ph.D. theses of over 30 graduate students in institutions other than his own. His recent collaborators include: G. Bacher, J.A. Borchers, A. Chang, O.D. Dubon, M. Grimsditch, B. Janko, G.A. Khodaparast, B.J. Kirby, S. Lee, H. Luo, Y.B. Lyanda-Geller, L. McNeil, R. Merlin, J.R. Meyer, G. Mihaly, L. Molenkamp, B. Nadgorny, E. Oh, H. Pascher, J.J. Rhyne, L.P. Rokhinson, P. Schiffer, N. Tolk, V.K. Vlasko-Vlasov, W. Walukiewicz, U. Welp, T. Wojtowicz, K.J. Yee, K.M. Yu, and Y.H. Zhang. Furdyna was a member of Editorial Boards of Semiconductor Science and Technology and Acta Physica Polonica; and in the past three years has been a member of Advisory or Program Committees of at least eight international conferences on semiconductor nanostructures and/or spin-electronic effects in solids.