Interacting excitons described by an infinite series of composite-exciton operators

M. Combescot (1) , O. Betbeder-Matibet (1)

1 INSP - Institut des Nanosciences de Paris

We revisit the approach proposed by Mukamel and co-workers to describe interacting excitons through infinite series of composite-boson operators for both the system Hamiltonian and the exciton commutator which, in this approach, is properly kept different from its elementary-boson value. Instead of free-electronhole operators, as used by Mukamel's group, we here work with composite-exciton operators which are physically relevant operators for excited semiconductors. This allows us to get all terms of these infinite series explicitly, the first terms of each series agreeing with the ones obtained by Mukamel's group when written with electron-hole pairs. All these terms nicely read in terms of Pauli and interaction scatterings of the composite-exciton many-body theory we have recently proposed. However, even if knowledge of these infinite series now allows us to tackle N-body problems, not just two-body problems like third-order nonlinear susceptibility chi((3)), the necessary handling of these two infinite series makes this approach far more complicated than the one we have developed and which barely relies on just four commutators.

Domaines: Matière Condensée [cond-mat]

M. Combescot, O. Betbeder-Matibet. Interacting excitons described by an infinite series of composite-exciton operators. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2008, 78 (12), pp.125206. ⟨10.1103/PhysRevB.78.125206⟩. ⟨hal-01287877⟩