Observation of Spin-Momentum-Layer Locking in a Centrosymmetric Crystal.
/ Authors
Kendra Zhang, Shixuan Zhao, Z. Hao, Shiv Kumar, E. Schwier, Yingjie Zhang, Hongyi Sun, Yuanyuan Wang, Yu-Jie Hao, Xiao-Ming Ma
and 10 more authors
Cai Liu, Le Wang, Xiaoxiao Wang, K. Miyamoto, T. Okuda, Chang Liu, J. Mei, K. Shimada, Chaoyu Chen, Qihang Liu
/ Abstract
The spin polarization in nonmagnetic materials is conventionally attributed to the outcome of spin-orbit coupling when the global inversion symmetry is broken. The recently discovered hidden spin polarization indicates that a specific atomic site asymmetry could also induce measurable spin polarization, leading to a paradigm shift in research on centrosymmetric crystals for potential spintronic applications. Here, combining spin- and angle-resolved photoemission spectroscopy and theoretical calculations, we report distinct spin-momentum-layer locking phenomena in a centrosymmetric, layered material, BiOI. The measured spin is highly polarized along the Brillouin zone boundary, while the same effect almost vanishes around the zone center due to its nonsymmorphic crystal structure. Our work demonstrates the existence of momentum-dependent hidden spin polarization and uncovers the microscopic mechanism of spin, momentum, and layer locking to each other, thus shedding light on the design metrics for future spintronic materials.
Journal: Physical review letters