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- A European team of researchers has discovered that new electronic states in the so-called topological insulator Bismuth Selenide could prove the key to room temperature operation of a radically new type of computing technology. The ubiquitous transistor, on which almost all electronics is based, relies on the ability to tune the electrical conductivity of a semiconductor by applying a small external voltage to move charge around. For decades, researchers have been aspiring to create a faster and more energy efficient transistor by utilizing a different fundamental property of the electron - its tiny magnetic moment known as
its spin. This goal has proved remarkably elusive as the so-called Rashba effect, on which this spin-transistor is based, is miniscule. Consequently, to feel a large enough effect, electrons must travel long distances without being kicked off their path. This is only possible if the whole device is kept at a temperature below −270°C - hardly a practical requirement for everyday use. Now, in a paper to be published in Physical Review Letters, it has been shown that Bismuth Selenide can support an electrostatically tuneable Rashba effect which is over one hundred times larger than in any other known semiconductor and persists well above room temperature. This sets the stage for building a spin-transistor to work at realistic temperatures, and may well provide the first practical applications of the newly-famed topological insulators.
