Exchange-correlation energy of a multicomponent two-dimensional electron gas

We discuss the exchange-correlation energy of a multicomponent (multivalley) two-dimensional (2D) electron gas and show that an extension of the recent parametrization [C. Attaccalite, S. Moroni, P. Gori-Giorgi, and G. B. Bachelet, Phys. Rev. Lett. 88, 256601 (2002)] of the exchange-correlation energy by Attaccalite describes well also the multicomponent system. We suggest a simple mass dependence of the correlation energy and apply it to study the phase diagram of the multicomponent 2D electron (or hole) gas. The results show that even a small mass difference of the components (e.g., heavy and light holes) decreases the concentration of the lighter components already at relatively high densities.