Roadmap on finding chiral valleys: screening 2D materials for valleytronics

In this review, we present an update on the methods for screening 2D materials suitable for valleytronic applications. We begin with an introduction to the field highlighting some of the latest findings and seminal works. Then we provide a brief background on the physics of valley- and layer- pseudospins in layered 2D materials such as transition metal dichalcogenides. This is followed by a detailed survey of a number of key techniques commonly employed to elucidate valley properties in such materials, highlighting in particular their capability for discriminating valley pseudospins, their key advantages and current limitations. Finally, we conclude by summarising the state-of-the-art assessing materials for valleytronic applications and point the reader to the current open questions that could have critical influence on the technological impact that may be derived from such materials.