Density-functional study of the magnetic and metal-insulator transition ofbcc hydrogen

A model body-centered cubic (bcc) hydrogen solid is studied using density f unctional theory in the local spin density approximation (LSDA) and in the generalized gradient approximation (GGA). In GGA, the paramagnetic to antif erromagnetic phase transition occurs at a higher density, and is in much be tter agreement with previous variational quantum Monte Carlo (VQMC) calcula tions than LSDA. The metal-insulator transition in GGA is observed at a hig her density and is also closer to the VQMC result than LSDA. In the limit o f isolated hydrogen atoms, we find that in GGA the self-consistent electron density is greatly improved over LSDA due to a better cancellation of the electronic self-interaction. [S0163-1829(98)06343-7].