Current dependent dephasing in an Aharonov-Bohm Interferometer

We have studied the temperature dependence of the current induced dephasing rate in a ballistic GaAs/Al$_{x}$Ga$_{1-x}$As ring. The dephasing rate is linearly proportional to the temperature regardless of the current applied. The AB oscillations are suppressed by the increase of the excitation current; however, the dephasing becomes less temperature dependent. Our observations cannot be interpreted by Joule heating effect. Possible decoherence mechanisms caused by the excess current will be discussed.