title: Nanocrystal shape and the mechanism of exciton spin relaxation.
abstract: The rate of exciton spin relaxation (flips) between the bright exciton states (F = +/-1) of CdSe nanocrystals is reported as a function of shape, for dots and nanorods. The spin relaxation is measured using an ultrafast transient grating method with a crossed linearly polarization sequence. It is found that the spin relaxation rate depends on the radius, not length, of the nanocrystals. That observation is explained by deriving an expression for the electronic coupling matrix element that mixes the bright exciton states.
authors.affiliation: Department of Chemistry, 80 St. George Street, Institute for Optical Sciences, and Centre for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6 Canada. gscholes@chem.utoronto.ca
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Scholes
authors.forename: Jeongho
authors.initials: J
authors.lastname: Kim
authors.forename: Cathy Y
authors.initials: CY
authors.lastname: Wong
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: Huxter
authors.forename: P Sreekumari
authors.initials: PS
authors.lastname: Nair
authors.forename: Karolina P
authors.initials: KP
authors.lastname: Fritz
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kumar
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry* / Q000528:radiation effects; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods; D008027:Light; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects; D045663:Quantum Dots; D013113:Spin Labels; D013440:Sulfides / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D019187:Cadmium Compounds; D013113:Spin Labels; D013440:Sulfides; C034939:cadmium sulfide