"Spin-optics", a new method for controlling electric current by manipulating electron spin-orbit interaction, can be used in semiconductors to achieve a wider spectrum of functionality similar to that achieved with polarized light. This method may be used for ultra-fast spin-based transistors.
Researchers at the Weizmann Institute of Science have discovered a novel method for controlling and manipulating the propagation of electrons in semiconductors with spin-orbit interaction by acting on the spin polarization of the electrons. It was found that when the spin-orbit coupling strength in the semiconductor is locally varying, electrons of different spin polarizations deflect by different angles at the region of the spin-orbit inhomogeneity. The spin-orbit coupling can be tuned locally and dynamically by applying bias voltage with gates. With suitable angle of incidence of electrons, one spin polarization either can pass through the region of inhomogeneity or totally reflected, in analogy to the total internal reflection phenomenon in optics. In fact, this new approach to spintronics is similar to manipulating polarized light in optical technologies. With this approach (termed "spin-optics") it is possible to manipulate the current carriers in semiconductors (electrons or holes) to achieve the whole spectrum of functionality used in optics of the polarized light, e.g., spin polarizing, spin filtering, switching, guiding as well as spin-based field effect transistor (spin-FET).