Service de Physique de l'Etat Condensé

Traditionally  in  condensed  matter  physics,  the  orbital  degree  of  freedom  has  been  regarded quenched.  Thus,  it  has  received  little  attention  and  overlooked  so  far,  compared  to  the  spin degree of freedom,  whose  study has  become a  promising  field  of  spintronics.  However,  recent works have shown that despite the orbital quenching in the ground state, the orbital information of electrons manifests as an active degree of freedom in transport and dynamic phenomena, in which electrons carry the orbital information. This has given rise to the emergence of a burgeoning field  of  research,  orbitronics,  which  exploits  the  orbital  degree  of  freedom  of  electrons  as  an information carrier.  
 
In this talk, I aim to deliver the essence of orbitronics – how the field has initiated, what are pivotal concepts, and why it is important. Then I will spotlight major achievements and state-of-the-art of orbitronics,  namely  orbital  Hall  effect,  orbital  Edelstein  effect,  and  orbital  torque.  These orbitronics phenomena are not only fundamentally important by themselves but also highly useful for spintronics as they provide more efficient ways to manipulate magnetization in broader range of materials. I will explain the theories that I proposed a few years ago and how they have been confirmed  by  experiments.  Despite  notable  advancements,  many  fundamental  aspects  remain shrouded in mystery. In the last part of my talk, I will discuss challenges in orbitronics and present my  proposal  to  overcome  these  challenges  and  turn  them  into  opportunities  for  investigating plethora of new orbitronics phenomena in novel material platforms such as molecular junctions, 2D materials, and oxide heterostructures, in collaboration with members of SPEC.
 
Coffee and pastries will be served