Spinning Holes in Semiconductors

Perhaps the most prominent characteristic of the electron is the fact that it carries electric charge. Together with the rules of quantum mechanics, the electric forces among electrons and nuclei determine the chemical properties of atoms and molecules. Manipulation of electrons in semiconductors using electric forces, which couple to the charge, is the principle behind the revolution in the electronics industry of the last few decades. Another fundamental feature of electrons is their spin, a property in which the charge apparently spins like a top, endowing the electron with a magnetic dipole moment much like that of a bar magnet. Incorporating and exploiting this spin in microelectronic and optoelectronic applications is the central idea of spintronics[1]. While a number of commercially successful applications of this already exist (most prominently as memory for computers), many proposed