Hall resistance hysteresis in AlGaN/GaN 2DEG

The Hall resistance of AlGaN/GaN two-dimensional electron gas (2DEG) at low temperatures was measured. The AlGaN/GaN heterostructures were grown by low-pressure metal-organic chemical vapor phase epitaxy on (0 0 0 1) SiC substrate. The electron mobility and electron concentration at View the MathML source are View the MathML source and View the MathML source, respectively.When the temperature is lower than View the MathML source the hysteresis of Hall resistance is observed near zero magnetic field. The hysteresis of Hall resistance increases with decreasing temperature. At temperatures higher than View the MathML source, the hysteresis of Hall resistance disappears. From the analysis of the residual Hall resistance dependence on the temperature, the Curie temperature of the Hall resistance hysteresis is calculated to be View the MathML source. In general, the hysteresis implies the possibility of ferromagnetism, but the conformation of the ferromagnetism of AlGaN/GaN heterostructure is still difficult and the detailed physical mechanism is still unclear.