Volume 55, Number 3, August 2001
|Page(s)||390 - 396|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||01 December 2003|
New criteria for bosonic behavior of excitons
Groupe de Physique des Solides, Université
Denis Diderot and Université Pierre et Marie Curie,
CNRS - Tour 23, 2 place Jussieu, 75251 Paris
Cedex 05, France
2 France Telecom R& D RTA/CDP - 196 avenue Henri Ravera 92225 Bagneux Cedex, France
Accepted: 18 May 2001
Dimensional arguments lead to say that N excitons in a sample of volume V behave as bosons for , ax being the exciton radius and λ a dimensionless factor. The Mott criterion, which is based on the disappearance of all exciton bound states because of screening, gives . Since excitons feel each other through both Coulomb interaction and Pauli exclusion between their electrons and holes, criteria based on the underlying fermionic character of the exciton should be even more relevant. Two significant quantities are the boson departure and boson number , where is the exciton creation operator. Their expectation values in the N-exciton state are close to their boson values for and , respectively. By contrast, the expectation value of in the vacuum state is close to N! for only. This surprising N2-dependence comes from the intrinsic N-body character of Pauli exclusion. Consequences of these new criteria on the Bose condensation of excitons are discussed.
PACS: 71.35.Lk – Collective effects (Bose effects, phase space filling, and excitonic phase transitions)
© EDP Sciences, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.