137 research outputs found
Excitons and biexcitons in symmetric electron-hole bilayers
Symmetric electron-hole bilayer systems have been studied at zero temperature
using the diffusion quantum Monte Carlo method. A flexible trial wave function
is used that can describe fluid, excitonic and biexcitonic phases. We calculate
condensate fractions and pair correlation functions for a large number of
densities rs and layer separations d. At small d we find a one-component fluid
phase, an excitonic fluid phase, and a biexcitonic fluid phase, and the
transitions among them appear to be continuous. At d = 0, excitons appear to
survive down to about rs = 0.5 a.u., and biexcitons form at rs > 2.5 a.u.Comment: 5 pages, 4 figure
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