摘要
Nonlinear effects of two-dimensional electron-gas systems at high magnetic fields are studied, and a current-driven instability is found to take place in magnetic fields corresponding to integer filling factors of Landau levels. The current instability is ascribed to the occurrence of a negative differential conductivity, predicted theoretically more than three decades ago. Physical origin of the negative differential conductivity is discussed and suggested to originate from an electric-field-induced reduction in the average scattering probability of electrons. © 2009 The American Physical Society.