One-dimensional Rashba states in Pb atomic chains on a semiconductor surface

We investigate the electronic and spin structure of Pb atomic chains on a $\mathrm{Si}(100)\ensuremath{-}2\ifmmode\times\else\texttimes\fi{}1$ surface using first-principles calculations. We revealed that the electronic spectra of linear dimerized Pb chains with orientations perpendicular and parallel to the Si dimers are characterized by one-dimensional large Rashba spin splitting providing exclusive spin polarization of the carriers that makes these systems suitable for studying the spin-transport phenomena and realizing a tunable spin current. A buckled dimerized Pb chain with a parallel orientation was predicted to be an insulating Rashba system with a vortical spin texture and asymmetric charge distribution. In this paper we trace the origin of Rashba band anisotropy and its interplay with chain geometry. The Rashba parameters of the considered chains are compared with other well-known systems.