Spinning electrons open the door to future hybrid electronics

A discovery of how to control spinning electrons paves the way for novel hybrid devices that could outperform existing semiconductor electronics. Researchers at LiU demonstrate how to combine a commonly used semiconductor with a topological insulator, a recently discovered state of matter with unique electrical properties. Just as the Earth spins around its own axis, so does an electron, in a clockwise or counter-clockwise direction. “Spintronics” is the name used to describe technologies that exploit both the spin and the charge of the electron. Current applications are limited, and the technology is mainly used in computer hard drives. Spintronics promises great advantages over conventional electronics, including lower power consumption and higher speed. In terms of electrical conduction, natural materials are classified into three categories: conductors, semiconductors and insulators. Researchers have recently discovered an exotic phase of matter known as “topological insulators”, which is an insulator inside, but a conductor on the surface. One of the most striking properties of topological insulators is that an electron must travel in a specific direction along the surface of the material, determined by its spin direction. This property is known as “spin-momentum locking”. “The surface of a topological insulator is like a well-organised divided highway for electrons, where electrons having one spin direction travel in one direction, while electrons with the opposite spin direction travel in the opposite direction. They can travel fast in their designated directions without colliding and without losing energy,” says Yuqing Huang, Ph D student at the Department of Physics, Chemistry and Biology (IFM) at Linköping University. These properties make topological insulators promising for spintronic applications. However, one key question is how to generate and manipulate the surface spin current in topological insulators.”