Diffusion and ballistic contributions of electron–electron interaction to the conductivity in an Al0.26Ga0.74N/AlN/GaN heterostructure

The results of an experimental study of quantum correction of electron–electron interaction (EEI) to the conductivity of two-dimensional electron gas (2DEG) in an undoped Al0.26Ga0.74N/AlN/GaN heterostructure are reported. A small but significant decrease of the Hall slope with the increase of temperature was discovered. This is not due to the increase of electron concentration as temperature increases but to the EEI effect. Both diffusion and ballistic contributions of EEI to the conductivity of 2DEG were observed. As the temperature increases, the negative diffusion EEI correction to the conductivity increases in an absolute value while the ballistic EEI correction reduces to a renormalization of the transport mobility.

► The electron–electron interactions are studied by magneto-transport measurements.
► The Hall slope decreases with the increase of temperature.
► The ballistic EEI correction reduces to a renormalization of the mobility.
► The diffusion EEI correction increases in absolute value with the temperature.