title: Electron-hole overlap dictates the hole spin relaxation rate in nanocrystal heterostructures.
abstract: Hole spin relaxation dynamics in CdTe/CdSe core-shell nanocrystals are measured by an ultrafast polarization transient grating technique. Photoexcited charge separation in type II structures suppresses the electron-hole exchange interaction and the hole spin relaxation time constant is found to increase from ∼0.3  ps to ∼10  ps at 293 K as the CdSe shell thickness increases from ∼0.2  nm to ∼2.4  nm. Analysis of these data suggests that spin relaxation in semiconductor nanostructures is tunable between type I and type II localization according to an electron-hole overlap function.
authors.affiliation: Department of Chemistry, Institute for Optical Sciences, and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Jun
authors.initials: J
authors.lastname: He
authors.forename: Haizheng
authors.initials: H
authors.lastname: Zhong
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Scholes