Europhys. Lett.
Volume 71, Number 3, August 2005
Page(s) 431 - 437
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 13 July 2005
Europhys. Lett., 71 (3), pp. 431-437 (2005)
DOI: 10.1209/epl/i2005-10101-8

Many-body origin of the "trion line" in doped quantum wells

M. Combescot1, J. Tribollet1, G. Karczewski2, F. Bernardot1, C. Testelin1 and M. Chamarro1

1  Institut des NanoSciences de Paris - Universités Paris-VI et Paris-VII CNRS UMR 75 88 - 140 rue de Lourmel, 75015 Paris, France
2  Institute of Physics, Polish Academy of Sciences Al. Lotnikow 32/46, 02-668 Warsaw, Poland

received 31 March 2005; accepted in final form 7 June 2005
published online 13 July 2005

We explain why the so-called "trion line" in the absorption spectrum of doped wells, cannot be due to a set of 3-body trions but has to come from a singular many-body object, intrinsically wide in energy: the photocreated virtual exciton dressed by Coulomb and Pauli interactions with the well carriers. This understanding is experimentally supported by the highly asymmetrical shape of the circular dichroism spectra obtained with a spin-polarized Fermi sea: their sharp edge on the low-energy side and significant tail at high energy are well explained by this many-body object, while they completely rule out a set of trions, either free or bound.

71.35.-y - Excitons and related phenomena.
71.35.Pq - Charged excitons (trions).
78.47.+p - Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter.

© EDP Sciences 2005