Current-induced hole spin polarization in a quantum dot via a chiral quasi bound state

Abstract

We put forward a mechanism for the current-induced spin polarization in semiconductor heterostructures, which is based on the complex structure of the valence band. It takes place for a light hole in a quantum dot side-coupled to a quantum wire with heavy holes. In stark contrast with the traditional mechanisms based on the linear in momentum spin–orbit coupling, an exponentially small bias applied to this structure is enough to create the 100% spin polarization in the quantum dot. Microscopically, this effect is related to the formation of the chiral quasi bound states and the spin-dependent tunneling of holes from the quantum wire to the quantum dot. This new concept is equally valid for the GaAs-, Si- and Ge-based nanostructures.