p-Wave Orbital Angular Momentum Texture in a Chiral Crystal

TL;DR

This study uncovers a p-wave orbital angular momentum texture in a chiral crystal using advanced spectroscopy, revealing dominant OAM polarization and potential for novel orbitronic applications.

Contribution

It provides the first experimental verification of a p-wave OAM texture in a crystalline material, linking OAM to lattice chirality and electronic properties.

Findings

Discovered a p-wave OAM texture in (TaSe4)2I

OAM polarization dominates over SAM in low-energy states

Revealed controllability of OAM by lattice chirality

Abstract

The spin and orbital angular momentum (SAM and OAM) are conceptually analogous, yet their roles in condensed matter systems have not been often treated on equal footing. While SAM has been extensively explored, OAM has long been regarded as quenched in crystalline environments and thus largely overlooked. Recent experimental and theoretical advances, however, have demonstrated that OAM can drive a variety of novel electronic phenomena, highlighting the importance of probing OAM textures in the electronic band structure. Here, we investigate the momentum-space OAM texture of (TaSe4)2I, a one-dimensional chiral crystal. Using circular-dichroism angle-resolved photoemission spectroscopy (CD-ARPES), we uncover a p-wave OAM texture accompanied by OAM dipole structures. This orbital p-wave texture is intimately connected to, and thus controllable by the chirality of the host lattice. Complementary spin-resolved ARPES measurements and first-principles calculations reveal that the OAM polarization overwhelmingly dominates the low-energy electronic properties of (TaSe4)2I, far exceeding the SAM polarization. These observations represent the experimental verification of a new type of OAM texture in crystalline materials. Most importantly, these findings underscore a promising material platform for spinless orbitronics applications and lay the foundation for realizing multipolar OAM textures-orbital counterparts of the spin texture in unconventional magnets.