Scanning Tunneling Microscopy Studies of Topological Nanostructures
Topological insulators (TIs) are a newly-discovered class of solid-state materials with remarkable properties and vast potential for exciting and novel applications. The electrons in these materials occupy states with a peculiar ‘topology’, which is a quantum mechanical property related to the classification of real-world solid objects according to their shapes. A doughnut cannot be transformed smoothly into a sphere, and so is a different class of object: similarly, the electronic states in a TI are completely distinct from those in normal materials, and hence have completely different properties.
Exploitation of these exotic effects in real world devices will require the engineering of tiny transistors, on the nanoscale. But in such nanostructures additional quantum effects become important which both threaten to destroy the original topology and provide new opportunities for engineering devices. We want to build a range of topological nanostructures, to test their topological properties as they become smaller and smaller, and to use the knowledge gained to engineer structures that will optimise device performance.
This work and is part of a project that has recently been funded by New Zealand’s most prestigious science funding agency, the Marsden Fund. More details will be added as time allows.
Schematic of a topological insulator showing edge states whose spin is locked to the electronic momentum.