Spin-momentum locking and correlated phenomena in chiral topological materials

Introduction

Chiral topological semimetals are a new class of quantum materials at the intersection of structural and electronic chirality. We discovered the first example of this material class three years ago and have since demonstrated that they host new fermionic quasiparticles without analogue in high-energy physics, which carry large and controllable topological charges.

Research Goals

ChiralTopMat will go beyond these initial works and aims to discover new extraordinary properties that have only been predicted for these materials but for which experimental evidence remains elusive:

1. A new form of isotropic parallel spin-momentum locking that can be considered the natural counterpart of Rashba spin-orbit coupling.
2. New electronic phases that are both correlated and topological.
3. Interface effects with magnetic materials that could be exploited for new energy-efficient information technology applications.

We will achieve these research goals by employing spin- and angle-resolved photoelectron spectroscopy on various energy scales, probing these materials' surface, bulk, and interface electronic structures.

Feasibility and Future Applications

Whilst the proposed experiments are challenging, our prior work and recent preliminary results have demonstrated their feasibility. If successful, ChiralTopMat will build on these discoveries to search for structure-property relationships that can be used to control these new phenomena by chemical and structural modification.

We envision that this new understanding will be the basis for future devices that exploit chiral topological semimetals for energy-efficient magnetic memory devices, which use multifold fermions for field-free switching of magnets with perpendicular magnetic anisotropy.