ABSTRACT
In the last chapter, we saw that Spin Transistors - whether they are of the ‘field effect’ type, or the ‘bipolar junction’ type - do not really yield significant advantages over their traditional charge based counterparts. Spin transistors are hybrid spin devices where charge still plays the dominant role. Digital information (i.e., binary bit 0 or 1) is ultimately encoded by charge. For example, in the case of the SPINFET, when charge flows through the channel of the transistor causing a source-to-drain current, the device is “on” and could encode the binary bit 1. When no current flows and the device is “off”, the encoded bit could be 0. Switching between logic bits is therefore associated with turning on or off a current, which involves physical motion of charges. This physical motion consumes considerable energy, which is ultimately dissipated as heat.
