In the Edelstein effect, a current in the crystal induces a spin polarization. It occurs in crystals without inversion symmetry, as studied in Rashba systems and in the surface of topological insulators. The spin polarization vanishes in equilibrium, but in the presence of the current, the off-equilibrium electron distribution leads to nonzero spin polarization, due to the spin-split band structure.
We propose an analogous effect for orbital angular momentum. For example, in a crystal with helical structure such as tellurium (Te), we propose that a current along the helical axis induces an orbital magnetization. This is analogous to solenoids in classical electrodynamics. Within this analogy to solenoids, we quantify this effect by introducing a dimensionless parameter, which represents a number of turns in the unit cell when regarded as a classical solenoid. We show that it can become much larger than unity, i.e. it is much larger than the value naïvely expected from the lattice structure.
Moreover, we propose a similar effect appears for phonons. In crystals, each phonon eigenmode has angular momentum due to rotational motions of the nuclei, but their sum is zero in equilibrium. Meanwhile a heat current in the Te crystal induces a nonzero total angular momentum. We evaluate this effect for GaN and Te by ab initio calculation, and propose experiments to measure this effect.
Conference Presentations are recordings of oral presentations given at SPIE conferences and published as part of the proceedings. They include the speaker's narration with video of the slides and animations. Most include full-text papers. Interactive, searchable transcripts and closed captioning are now available for most presentations.
Search our growing collection of more than 22,000 conference presentations, including many plenaries and keynotes.