Speaker: Tatiana Rappoport (Universidade Federal do Rio de Janeiro & Instituto de Telecomunicações - Lisboa)
Abstract: A renewed interest in orbital magnetism and other orbital effects in solids raises expectations that orbital angular degrees of freedom may be eventually employed to process information in logic and memory devices. This next-generation technology has been coined as orbitronics and utilizes the orbital current as an information carrier.
The orbital Hall effect (OHE), similarly to the spin Hall effect (SHE), refers to the creation of a transverse flow of orbital angular momentum that is induced by a longitudinally applied electric field. I will discuss different aspects of the OHE in 2D materials. In particular, I will show that monolayers and bilayers of transition metal dichalcogenides (TMDs) like MoS2 and WSe2, exhibit OHE in its insulating phase. The orbital Hall conductivity presents a plateau in the semiconductor gap of these materials that can be associated with a topological phase characterized by an orbital Chern number. Our results offer the possibility of using TMDs for orbital current injection and orbital torque transfer that surpass their spin equivalents. I will also explore the connection between the orbital Hall effect and the valley Hall effect in 2D materials.
