Many technical equipments are based on traditional semiconductor electronics. The charging current is used to store and process the information in these components. However, this current will cause heat and energy loss. In order to solve this problem, spintronics uses a basic property of electrons, namely spin. "This is an inherent angular momentum, which can be imagined as an electron rotating around its own axis," explained Dr. annika Johnson, a physicist at the University of Maryland. Spin is related to magnetic moment, and besides the charge of electrons, it can be used in a new generation of fast and efficient components.
In order to achieve this, effective conversion between charge and spin current is needed. Edelstein effect makes this conversion possible: by applying an electric field, a charge current is generated in the original nonmagnetic material. In addition, the electron spins align and the material becomes magnetic. "Previous papers on Edelstein effect mainly focused on how electron spin contributes to magnetization, but electrons can also carry orbital moments that also contribute to magnetization. If the spin is the inherent rotation of the electron, then the orbital moment is the motion around the nucleus, "Johansson said. This is similar to the earth, which rotates around its own axis like the sun. Like spin, this orbital moment produces a magnetic moment.
In this latest study, researchers use simulation to study the interface between two oxide materials commonly used in spintronics. Johansson said: "Although these two materials are insulators, there is a metallic electron gas at their interface, which is famous for its effective charge-spin conversion." The team also incorporated orbital moment into the calculation of edelstein effect, and found that the contribution of orbital moment to edelstein effect is at least one order of magnitude greater than that of spin. These findings are helpful to improve the efficiency of spintronic devices.