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Spin Engineering in Magnetic Quantum Well Structures

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Spin Engineering in Magnetic Quantum Well Structures UNIVERSITY OF CALIFORNIA Santa Barbara Spin Engineering in Magnetic Quantum Well Structures s d A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Materials Science by Roberto Correa Myers Committee in charge: Professor David Awschalom, Co-Chairperson Professor Arthur Gossard, Co-Chairperson Professor Evelyn Hu Professor Pierre Petroff Professor James Speck December 2006 The dissertation of Roberto Correa Myers is approved: September 2006 Spin Engineering in Magnetic Quantum Well Structures Copyright © 2006 by Roberto Correa Myers iii To my abuelos and grandparents, Elvira and Ricardo Correa, Betty and Vernon Myers iv Acknowledgments My life in graduate school has, without question, been nothing but fun. I was un- believably lucky during my studies both personally and professionally. Mostly this good fortune involves having met, worked, and played with so many tal- ented, funny, and entertaining friends and colleagues, many of whom I hope to remain lifelong friends with. The beginning of my luck was becoming a stu- dent of my advisors, David Awschalom and Art Gossard. Both Art and David have built unusually successful research groups, which by virtue of their close proximity and collegiality, have made astounding research progress at a pace not possible anywhere other than in Santa Barbara. They are both true individ- uals, both inspiring and entertaining, with flavorful character and experience. David’s ability to maintain an incredible pace of innovative research is well known. Without a doubt, David is one of the most rewarding and enjoyable professor to work with. Art’s Zen-like aura and chivalrous style are legendary in the semiconductor community. He is always available with keen advice and infinite patience, quintessentially the perfect role model. Fortune found me in Art’s lab, the best MBE center I know of. Who taught me to grow samples? Danny Driscoll and Micah Hansen, the old-guard of famed system C, showed me how you run and maintain an MBE system, taught me the traditions of beer 30, and pub-crawling. Zeke Johnston-Halperin taught me the tricks of magnetic semiconductor growth and how to measure these sam- ples. I’m also indebted to him for his lab example in managing collaborations and running experiments, for which I will remain his most humble and obedient servant. John English is responsible for keeping the MBE lab from exploding on any given day, for maintaining a spirit of camaraderie, and for being a lim- itless fountain of technical expertise. Both his and Art’s wisdom, consistency, and dedication have allowed the MBE lab to flourish through the years. Andrew Jackson deserves praise for countless improvements to the spintronics lab, for example using his entrepreneurial-style and MBE skills to locate, disassemble, transport, and install an MBE system in a few months...and then do it a again a couple more times for some profit; I also thank him for letting me drive his Audi v S4 at ridiculous speeds on the 101, borrow his African drum, and his surfboard. Jason Stephens is thanked for helping co-manage the MBE system. Spintronics- growers: Roland Kawakami, Ted Kreutz, Chad Gallinat, Mark White, Francisco Bloom, and Shawn Mack are also thanked for turning bolts and risking getting arsenic poisoning with me. I’m comforted to know that the system will be left in Shawn’s capable hands. Antonio Badolato, Brian Gerardot, Jeramy Zimmer- man, Josh Zide, Christoph Kadow are thanked for keeping system C running. Dave Buell, Max Andrews, Mel Maclaurin, Christy Poblenz, Sidarth Rajan, Dan Loftgreen, Dave Buell, Chad Wang, Andrea Corrion, and Moe are thanked for setting great examples of materials research while keeping the lab lively. Whilst plodding about campus, I luckily found myself in David’s optics lab. I particularly thank Scott Crooker for writing an excellent thesis. Much of my own work followed directly from his experiments, chapter 4. Dr. Ines Meinel, now a surfer girl, provided my first tutelage in low temperature physics and was quite patient with my initial clumsiness. Darron Young and Jay (now professor) Gupta are thanked for their dedication to goofiness and howling in the optics-lab. Yuichiro Kato, aside from being an astoundingly clever physi- cist and a general all-around happy guy, is a man of character. He is thanked for joining me in drinking beers (sometimes on a roof), touring me through his country, and acting in a movie. My highly distinguished friend, Nate Stern (team-Mn), is thanked for measuring samples, seemingly, before I even grew them and putting up with ridiculous arguments between the other members of team-Mn. Felix Mendoza is particularly thanked for paying the bills on time, getting me out of quite a few jams, and having a good sense of direction. Jesse Berezovsky is praised for his musical taste, hookah smoking, and dancing feats. Vanessa Sih runs in short, unpredictable bursts, and sometimes brings baked goods. I thank Hadrian Knotz for sharing his ski chalet and inspiring the “can- tenna”. I’ve had the pleasure to get to know and collaborate with many talented postdocs: Geoff Steeves, a Canadian I can call friend, Alex Holleitner, my surf- ing doppleganger, Min Ouyang, Yongqing Li, Dave Steuerman, Wayne Lau, Ronald Hansen, Oliver Gwyant, Florian Meier, and Sai Ghosh. Good luck to the newer students: Maiken Mikkelsen, Viva Horowitz, William Koehl, Mark vi Nowakowski, and Brian Maertz. I’ve benefitted from collaborations with our Penn State friends: K-C Ku, Ben-Li Sheu, X. Li, Nitin Samarth, and Peter Schiffer. The CNSI staff led by Holly Wu, are praised for their consistency in keeping everything running smoothly, and for being patient with my timecard. Martino “Tino”, “Pogg” Poggio has been my comrade in capers both sci- entific and nautical. His scientific skills and energy were instrumental to this research, while at the same time helping me sink sailboats and bring traffic lights down. Pogg (team-Mn) was the Chair of the now defunct Smelrose Institute and a banjo player in the Shanty-town players (slanty). His knack for story telling and goofy conversation are sorely missed. The frequent and heated arguments, although draining, always lead to an enlightening perspec- tive. Jon “Butts” Miller was the director of said institute, co-founder of SLOW, a singer in the shanty, and co-developer of various other scams, such as the Es- cher Auto-baster, and without whom the shanty is not nearly slanty enough. I thank the other members of the institute and collaborators: Kristen “the pad- dler” Madler, Chelsey and Bailey Swanson, Steeve-o Harding, R1 and M2 Ras- mussen, Vanessa Silva, Erin Muslera, Ken and Kyra, Sarita, Sara Fretwell, Ryan Aubry for festival of life, T-day extravaganza’s, BBQ’s, concerts, surfing, sing- alongs, and for keeping me aware of society outside of the crunchy-science taco shell. The Via Regina crew: Rob (slanty), Rosco and Val, Jon and Amy, Mike and Jersey are praised for living the sweet life. Jason [and Kirsten] Haaheim, Jill Heinke, Jeff Danziger, the original mem- bers of the RJ3 quartet are thanked for letting me jam with them, thereby pro- tecting my sanity. Other musical collaborators I thank are Kristin Wiseman, April Windsor, Tommy, Rob Wallace, Ralph Lowi, Max Katz, Colter Frazer, Chris Teeples, and the gang. I still think we could make it big someday. Mi linda amor, Maria, I thank for making my last year in school the greatest one of all. All the extended families, Myers, Perreira, Griggs, Maitra, Cor- rea, Roca de Togores, Guerra, Onofryton, Carrington, Rezazadeh, are the most highly entertaining, diverse, and interesting people I know. My family has been loving and supportive through the years: My parents Albert and Mayra put up vii with me “repairing” many things, my big sister Natasha (Jorge and Sophia), my little sister Rosie, and my little brother Timmy. Abuela, Elvira, always sup- ported me to pursue science, and my abuelo Ricardo taught me the joy of build- ing. My grandparents Betty and Vernon, both excellent scientist and teachers, are my inspiration and role models. viii Vitæ Education 2001 B.S.E. Materials Science and Engineering cum laude B.A. Philosophy and Science cum laude University of Pennsylvania, Philadelphia, PA 2006 Ph.D. Materials Science University of California, Santa Barbara, CA Publications Magnetic quantum wells “Confinement engineering of s-d exchange interactions in GaMnAs quan- tum wells”, N. P. Stern, R. C. Myers, M. Poggio, A. C. Gossard, and D. D. Awschalom, cond-mat/0604576 (submitted). “Structural, electrical, and magneto-optical characterization of paramag- netic GaMnAs quantum wells”, M. Poggio, R. C. Myers, N. P. Stern, A. C. Gossard, and D. D. Awschalom, Phys. Rev. B 72, 235313 (2005). “Optoelectronic control of spin dynamics at near-terahertz frequencies in magnetically doped quantum wells”, R. C. Myers. K. C. Ku, X. Li, N. Samarth, and D. D. Awschalom, Phys. Rev. B 72, 041302(R) (2005). “Antiferromagnetic s-d Exchange Coupling in GaMnAs”, R. C. Myers, M. Poggio, N. P. Stern, A. C. Gossard, and D. D. Awschalom, Phys. Rev. Lett. 95, 017204 (2005). “Tunable spin polarization in III-V quantum wells with a ferromagnetic bar- rier”, R. C. Myers, A. C. Gossard, and D. D. Awschalom, Phys. Rev. B 69, 161305(R) (2004). ix Ferromagnetic semiconductors and heterostructures “Antisite effect on ferromagnetism in (Ga,Mn)As”, R. C. Myers, B. L. Sheu, A. W. Jackson, A. C. Gossard, P. Schiffer, N. Samarth, and D. D. Awschalom, cond-mat/0606488 (submitted). “Tunneling through MnAs particles at a GaAs p+n+ junction”, F. L. Bloom, A. C. Young, R. C. Myers, E. R. Brown, A. C. Gossard, and E. G.
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