The Center for Nanoscale Materials holds a regular biweekly colloquium on alternate Wednesday afternoons at 4:00 p.m. in Bldg. 440, Room A105/106. The goal of the series is to provide a forum for topical multidisciplinary talks in areas of interest to the CNM and also to offer a mechanism for fostering interactions with potential facility users. Refreshments will be served at 3:45.
April 23, 2014
"Designing Materials at the Nanoscale: Semiconductor and Graphene Quantum Dots," by Pawel Hawrylak, National Research Council of Canada, hosted by Stephen Gray
Abstract: We review here recent theoretical and experimental results on designing materials at the nanoscale: semiconductor and graphene quantum dots. We briefly describe lateral quantum dot molecules as building blocks of quantum circuits based on electron spin: artificial Haldane gap device, GHZ maximally entangled state, Berry's phase, and e-e driven topological phase generators. We next turn to the locking of spin and orbital motion and emergence of tunable topologically protected chiral surface states in HgTe quantum dots. Finally, we describe one-atom-thick semiconductor quantum dots made of graphene and compare them with semiconductor quantum dots. We show how their electronic, optical, and magnetic properties can be engineered by the size, shape, type of edge, topology, and number of layers. Preliminary comparison of theory with experiment on optical properties of colloidal graphene quantum dots will be made.