The crystal, spin, and electronic structure of the "111"-type LiFeAs superconductor has been investigated by first-principles calculations based on the density-functional theory. It is found that the crystal structure and weak magnetism of metallic LiFeAs can be described by general gradient approximation and local spin-density approximation (LSDA). Both methods show LiFeAs is a weak correlated system with a striped antiferromagnetic ground state and the easy axis of magnetization is along the b direction of the magnetic unit cell. The magnetic unit cell is distorted from the tetragonal into an orthorhombic structure. The spin moment/Fe calculated by the LSDA method is 0.121 mu(B).

antiferromagnetic materials; crystal structure; density functional theory; electronic structure; fluctuations in superconductors; ground states; iron compounds; lithium compounds; magnetic moments; magnetisation; spin fluctuations

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