Sa. Brown et al., TIME-RESOLVED MAGNETOPHOTOLUMINESCENCE MEASUREMENTS OF THE INTEGER QHE, FRACTIONAL QHE AND EXTREME QUANTUM LIMIT, Surface science, 305(1-3), 1994, pp. 42-49
Low-temperature, time-resolved magneto-photoluminescence (TRPL) measur
ements of 2D electron-free-valence-hole recombination have been carrie
d out in the IQHE, FQHE and magnetically induced electron solid regime
s of a GaAs/AlGaAs single heterojunction. Clear differences, not prese
nt at elevated temperatures, are found in the measured PL decay time (
approximately 1 ns) for components of multiple-peak structure observed
beyond nu = 1/5 used previously to construct a phase diagram associat
ed with the Wigner solid. The new TRPL results and earlier PL data, ta
ken together, are consistent with a mechanism in which the spectral fe
ature associated with crystallisation derives from the trapping of exc
itons within a few Bohr radii (z separation) of the heterointerface an
d their subsequent (x, y) localisation by the presence of a 2D electro
n system with a degree of spatial order at this interface.