Many‐Body Theory for the Dense Exciton Gas of Direct Semiconductors II. Calculation of Exciton Level Shift and Damping in Dependence on Exciton Density

Abstract

The spectral properties of a dense exciton gas are discussed using an exciton self-energy in second collisional Born approximation with respect to exciton-exciton interaction. The shift of the continuum edge and the 1s exciton as well as the increase of the damping of the 1s exciton are calculated linearly in the exciton density. The distribution of 1s excitons is assumed to be either a macro-occupation of the k = 0 state or a Boltzmann distribution with effective temperature varying between 10 and 60 K. A weakening of the level shift is obtained with increasing temperature. I n the case of macro-occupation damping is calculated self-consistently resulting in a sublinear dependence on density.Die Spektraleigenschaften eines dichten Exzitonengases werden bei Benutzung einer ExzitonSelbstenergie in zweiter Bornscher Nflherung in bezug auf die Exziton-Exziton-Wechselwirkung diskutiert. Sowohl die Shifts der Kontinuumskante und des 1s-Exzitons als auch das Anwaohsen der Dflmpfung des 1s-Exzitons werden linear in der Exziton-Dichte berechnet. Die Verteilung des 1s-Exzitons wird entweder als Makrobesetzung des k = 0-Zustandes oder als Boltzmann-Verteilung mit einer effektiven Temperatur, die zwischen 10 und 60 K variiert wird, angesetzt. Der Shift wird mit zunehmender Temperatur abgeschwacht. I m Falle der Makrobesetzung wird die Dampfung selbstkonsistent berechnet, was zu einer sublinearen AbhSngigkeit von der Dichte fuhrt.

Transient four-wave mixing in T-shaped GaAs quantum wires

“…An exciton-exciton scattering proportional to the exciton density was found in theory 58 and in experiments on bulk GaAs ͑Ref. 59͒ and GaAs QW's.…”

“…To compare with theory, 58,61 ⌫ XX (T) can be normalized to the dimensionless scattering parameter ␥ XX (T)ϭ⌫ XX (T)/(E X a B n ) using the exciton binding energy E X , the Bohr radius a B , and dimensionality n. Experimental values from literature on systems of different dimensionality are reported in Table I.…”

Intervalley biexcitons and many-body effects in monolayerMoS2

“…As anticipated in highly excited semiconductors, photoexcited carriers introduce additional screening and modify exchange-correlation energies [30][31][32][33][34] . Renormalization of the electronic structure gives rise to the reduction of both the band gap and the exciton binding energy.…”

Coherent optical nonlinearities and phase relaxation of quasi-three-dimensional and quasi-two-dimensional excitons inZnSxSe1−xWägner1, Schätz2, Maier3 et al. 1997Phys. Rev. B354110View full textAdd to dashboardCite

“…6͑a͒ as a function of the exciton density. The linear increase of ␥ hom is due to an excitonexciton collision broadening, 46,47 which can be described by…”