Spin-orbit torques

The spin-orbit interaction for controlling various spin states

The coupling of spin and motion mediated by the spin-orbit interaction can provide a bi-lateral access of these two quantities - spin & motion (or transport), of electrons. As a result, the spin-orbit interaction can empower us to control electron spins through electric excitations - it seems we have better controllabilities of charge than spin as history explains. Electrons in a crystal with broken inversion symmetry experience different energy levels determined by the directions of both motion and spin. Controlling the motional component (by applying a current through), we can therefore access to the electron spin population. This is  a current-induced spin polarisation and if one does this in ferromagnetic materials, you can also control the localised electron spins that is hardly susceptible to applying a current - that's why they are called "localised". We are in part of an active international research collaboration (with many world-leading researchers in the world), and attempt to understand the microscopic pictures of current-induced spin polarisation and mangetisation control, in as view of harnessing for technology. Some details of this would be found in the following papers.

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