Observation of a fractional quantum hall state at nu = 1/4 in a wide GaAs quantum well.

We report the observation of an even-denominator fractional quantum Hall state at nu = 1/4 in a high quality, wide GaAs quantum well. The sample has a quantum well width of 50 nm and an electron density of n(e) = 2.55 x 10(11) cm(-2). We have performed transport measurements at T - 35 mK in magnetic fields up to 45 T. When the sample is perpendicular to the applied magnetic field, the diagonal resistance displays a kink at nu = 1/4. Upon tilting the sample to an angle of theta = 20.3 degrees a clear fractional quantum Hall state emerges at nu = 1/4 with a plateau in the Hall resistance and a strong minimum in the diagonal resistance.