Characterisation of Topological States

Topological edge and surface states have unique electronic properties which make them promising candidates for applications, e.g. in quantum computing. Using scanning probe techniques, we study the local properties of topological boundary states in layered materials.

Topological materials have in common an inverted band structure that results in topologically protected boundary states at interfaces bordering to a topologically trivial material, including vacuum. The material class of Bi2Te3 is a prototypical three-dimensional topological insulator, with two-dimensional Dirac cone-like surface states, which we have studied extensively in the past [1, 2, 3, 4]. When induced with magnetism, in form of MnBi2Te4, we are further able to study the interplay of magnetism and topology [5].

By incorporating layered topological insulators into heterostructures, we are able to engineer topological superconductors [6] which can host so-called Majorana states and are proposed to have applications in topological quantum computing.

Characterisation of Topological States
STM topography and tunnelling conductance measured across a WTe2 ML-BL step edge , showing an increase in the density of states due to presence of a quantum spin Hall boundary state.
ACS Nano Letters

Last Modified: 12.07.2024