HIGH-FIELD PHOTOLUMINESCENCE IN GAAS SINGLE HETEROJUNCTIONS - MAPPING OF AN OPTICALLY DETERMINED PHASE-BOUNDARY CORRELATED WITH THE ELECTRON LIQUID SOLID TRANSITION

Bandgap magneto-photoluminescence is used to study the optical signature of a high-quality, low-density GaAs AlGaAs heterojunction in the integer QHE, fractional QHE and Wigner regimes. In the extreme quantum limit an intense, new spectral feature is observed to emerge for v < 1/5, the temperature dependence of which is used to define two characteristic temperatures, T(c1) and T(c2). The boundary formed by the lower mapping, T(c1), in the (B,T)-plane correlates well with the electron liquid-solid transition established by other techniques.