Spintronics without magnetism

Recently, David Awschalom(UCSB) and Nitin Samarth (Penn State) published an interesting article on the development of this alternate track—“spintronics without magnetism”—relies on our ability to manipulate carrier spins in semiconductors through the spin-orbit interaction. This is an attractive pathway for designing semiconductor spintronic devices because spin-orbit coupling enables the generation and manipulation of spins solely by electric fields. This is easy to understand in a qualitative way by recalling that spin-orbit coupling is the natural outcome of incorporating special relativity within quantum mechanics (the Dirac and Pauli equations). In the rest frame of an electron moving through a lattice, the external electric field (along with that from the atomic cores) is Lorentz transformed into a magnetic field that can act upon the spin of the electron. Using the spin-orbit interaction for manipulating electron spin obviates the design complexities that are often associated with incorporating local magnetic fields into device architectures. As we discuss below, the basic conceptual framework for the influence of the spin-orbit interaction on mobile electron spins has deep and old roots, but the experimental harnessing of these concepts is very contemporary and still at an early—and exciting—stage of development and discovery.

For the complete article click here