Weakly correlated one-dimensional indium chains on Si(111)

Quasi-one-dimensional (1D) metals often exhibit a broken symmetry state. Here our first-principles density-functional theory calculations show that quasi-1D indium chains on the Si(111)-(4×1) surface are stabilized with (4×2) or (8×2) symmetry by lattice distortions of the two zigzag indium rows composing the chain. The ground state is almost degenerate, consistent with recent experiments which indicate that several phases coexist at low temperature.