L. Liu et al., EXCITON AND CHARGE-DENSITY-WAVE FORMATION IN SPATIALLY SEPARATED ELECTRON-HOLE LIQUIDS, Physica. B, Condensed matter, 251, 1998, pp. 594-597
We present a microscopic many-body calculation investigating the compe
tition between the charge density wave and exciton formation in couple
d electron-hole layer systems at finite temperature. We find that as t
he layer separation is decreased there is a divergence at a finite wav
e vector in the static susceptibility, indicating an instability in th
e liquid to a coupled charge density wave. We also see evidence in the
pair correlation function g(r) for the liquid phase of a divergence o
ccurring at small r when the layer separation is reduced sufficiently,
which would indicate the onset of a bound state instability. However,
the charge density wave instability occurs in the liquid before g(r)
can actually diverge. The unified picture which starts to emerge from
our results is of a charge density wave instability occurring in the l
iquid phase at a layer separation larger than the exciton radius. This
leaves open the possibility of a second transition from the charge de
nsity wave state to the excitonic phase. (C) 1998 Elsevier Science B.V
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