ON THE PEIERLS DISTORTION AND THE LOCAL-DENSITY APPROXIMATION

We present the results of first-principles, density-functional calculations on isolated, single, infinite zig-zag chains of nitrogen atoms and on isolated, single, infinite linear chains of carbon atoms. Exchange and correlation effects were treated within a local approximation and special emphasis was put on whether the calculations yielded a structure with alternating bond lengths as that with the lowest total energy (i.e. on whether a Peierls' distortion was found) as well as on the dependence of the results on the sampling in the one-dimensional k space.