Emerging Spin-Orbit Torques in Low-Dimensional Dirac Materials.

We report a theoretical description of novel spin-orbit torque components emerging in two-dimensional Dirac materials with broken inversion symmetry. In contrast to usual metallic interfaces where fieldlike and dampinglike torque components are competing, we find that an intrinsic dampinglike torque which derives from all Fermi-sea electrons can be simultaneously enhanced along with the fieldlike component. Additionally, hitherto overlooked torque components unique to Dirac materials emerge from the coupling between spin and pseudospin angular momenta, leading to spin-pseudospin entanglement. These torques are found to be resilient to disorder and could enhance the magnetic switching performance of nearby magnets.

Copropagating Edge States Produced by the Interaction between Electrons and Chiral Phonons in Two-Dimensional Materials.

Unlike the chirality of electrons, the intrinsic chirality of phonons has only surfaced in recent years. Here, we report on the effects of the interaction between electrons and chiral phonons in two-dimensional materials by using a nonperturbative solution. We show that chiral phonons introduce inelastic Umklapp processes resulting in copropagating edge states that coexist with a continuum. Transport simulations further reveal the robustness of the edge states. Our results hint on the possibility of having a metal embedded with hybrid electron-phonon states of matter.