2024 roadmap on 2D topological insulators

TL;DR

This paper provides a comprehensive update on the progress, challenges, and future directions of 2D topological insulators, highlighting their fundamental physics, material developments, and potential applications in quantum and spintronic devices.

Contribution

It offers a detailed roadmap summarizing recent advances and outlining future research directions in the field of 2D topological insulators.

Findings

Several materials with sizable bulk gaps suitable for room-temperature applications

Progress in heterostructure integration with functional materials

Potential for topological quantum computing via induced superconductivity

Abstract

2D topological insulators promise novel approaches towards electronic, spintronic, and quantum device applications. This is owing to unique features of their electronic band structure, in which bulk-boundary correspondences enforces the existence of 1D spin-momentum locked metallic edge states - both helical and chiral - surrounding an electrically insulating bulk. Forty years since the first discoveries of topological phases in condensed matter, the abstract concept of band topology has sprung into realization with several materials now available in which sizable bulk energy gaps - up to a few hundred meV - promise to enable topology for applications even at room-temperature. Further, the possibility of combining 2D TIs in heterostructures with functional materials such as multiferroics, ferromagnets, and superconductors, vastly extends the range of applicability beyond their intrinsic properties. While 2D TIs remain a unique testbed for questions of fundamental condensed matter physics, proposals seek to control the topologically protected bulk or boundary states electrically, or even induce topological phase transitions to engender switching functionality. Induction of superconducting pairing in 2D TIs strives to realize non-Abelian quasiparticles, promising avenues towards fault-tolerant topological quantum computing. This roadmap aims to present a status update of the field, reviewing recent advances and remaining challenges in theoretical understanding, materials synthesis, physical characterization and, ultimately, device perspectives.