title: Multiexciton generation by a single photon in nanocrystals.
abstract: We have theoretically shown that efficient generation of multi-electron-hole pairs by a single photon observed recently in semiconductor nanocrystals1-4 is caused by breaking the single electron approximation for carriers with kinetic energy above the effective energy gap. Due to strong Coulomb interaction, these states form a coherent superposition with charged excitons of the same energy. This concept allows us to define the conditions for dominant two-exciton generations by a single photon: the thermalization rate of a single exciton, initiated by light, should be lower than both the two-exciton state thermalization rate and the rate of Coulomb coupling between single and two exciton states. Possible experimental manifestations of our model are discussed.
authors.affiliation: Center for Computational Material Science, Naval Research Laboratory, Washington, DC 20375, USA. ashabaev@gmu.edu
authors.forename: A
authors.initials: A
authors.lastname: Shabaev
authors.forename: Al L
authors.initials: AL
authors.lastname: Efros
authors.forename: A J
authors.initials: AJ
authors.lastname: Nozik