Optical properties of a two-dimensional electron gas at even-denominator   filling fractions
  The optical properties of an electron gas in a magnetic field at filling fractions \nu = {1\over 2m} (m=1,2,3...) are investigated using the composite fermion picture. The response of the system to the presence of valence-band holes is calculated. The shapes of the emission spectra are found to differ qualitatively from the well-known electron-hole results at zero magnetic field. In particular, the asymmetry of the emission lineshape is found to be sensitive to the hole-composite fermion plane separation. 
Darren J. T. Leonard (1), Neil F. Johnson (1), V. Nikos Nicopoulos (1)   and F. J. Rodriguez (2) ((1) Oxford University, (2)...