Effect of two-body and three-body correlations on the diffusion constant of two-dimensional Coulomb systems in a uniform magnetic field

We calculate the diffusion constant of a two-dimensional electron gas (2DEG) in a uniform perpendicular external magnetic field using the short-time expansion of the Kubo–Greenwood formula. We model the 2DEG as a one-component plasma. The two-body and three-body correlation functions are obtained from the hypernetted-chain integral equation theory and the Kirkwood superposition approximation, respectively. We compare the diffusion constant at two different temperatures. At the lower temperature, the diffusion constant increases as the magnetic field is increased but decreases with increasing magnetic field at the higher temperature. We compare our results when only two-body correlations are taken into account with those when both two-body and three-body correlations are included. These results may be interpreted as being due to the competition between the magnetic force and the force exerted on the target particle by the surrounding electrons in the 2DEG in the presence of a perpendicular magnetic field.