Competition between neighboring minima in the fractional quantum hall effect.

We report observations of a temperature dependent competition in the fractional quantum hall effect in GaAs/AlGaAs heterostructures. Two pairs of neighboring minima in the diagonal resistance rho(xx) versus magnetic field exhibit a competition by which the stronger minimum engulfs the weaker minimum as the temperature is decreased. This competition is observed at fractional Landau filling factor nu between the minima at nu = 7/5 and 4/3, and the minima at nu = 8/5 and 3('). The development of the minima at nu = 4/3 and 5/3 relative to one another has a magnetic field and temperature dependence which contrasts with the development of the nu = 1/3 and 2/3 minima.