Topological states

TL;DR

This paper reviews various topological phases in materials, highlighting their invariants, types, and potential device applications, emphasizing recent advances in topological insulators, semimetals, and quantum devices.

Contribution

It provides a comprehensive overview of topological states, their material realizations, and emerging device applications, summarizing recent progress in the field.

Findings

Topological phases are characterized by invariant properties unaffected by Hamiltonian deformations.

Materials like topological insulators and Weyl semimetals exhibit unique electronic states.

Potential device applications include topological transistors and quantum bits.

Abstract

Topological phases are characterised by a topological invariant that remains unchanged by deformations in the Hamiltonian. Materials exhibiting topological phases include topological insulators, superconductors exhibiting strong spin-orbit coupling, transition metal dichalcogenides, which can be made atomically thin and have direct band gaps, as well as high mobility Weyl and Dirac semimetals. Devices harnessing topological electron states include topological (spin) transistors, spin-orbit torque devices, non-linear electrical and optical systems, and topological quantum bits.